When Indonesia wants to do business with the U.S. military, a company in Jakarta can supply a valuable friend in court for the governments and industries of both nations.

His name is Angelo Grills. He is a former U.S. Army colonel who after heading the Defense Department Liaison Group in Indonesia for two years, retired and took a job as vice president of an Indonesian firm that is the agent for several major U.S. defense contractors.

While working for the Pentagon in Indonesia Grills was one of several U.S. officials who served as condits and negotations on requests by the Indonesian government for arms purchases from the United States.

The company he has gone to work for P T Sunda Karya derives part of its income from U.S. arms sales to Indonesia. As agent for a number of defense contractors. Karya receives a fee on all sales of those companies' products to Indonesia.

Indonesia, like Japan and serveral other nations, requires that a native company be involved in most large foreign commerical transactions.

Grills' new job is novel variation on the "revolving-door" theme that has come under increasing criticism on Capitol Hill. Whereas the usual revolving door involves high-ranking Defense officials leaving the service to go to work for defense contractors. Grills has taken a slightly different route by working for an agent of the defense contractors.

Sen. William Proxmire (D-Wis) has introduced a bill that would bar military officers involved in awarding contracts from accepting employment with companies that received contracts the officers worked on for two years after they leave the service.

The bill also would establish a three-man review board, headed by the chairman of the Civil Service Commision, to review marginal cases like Grills'. The bill has been approved by the Senate Banking Committee and awaits action by the full body.

In a related development, Comptroller General Elmer B. Staats announced last month that former military officers employed by defense contractors who provide entertainment of favors to procurement officers risk loss of their military pensions.

Grills served as chief of the Defense liasion office from July, 1974, to September, 1976. One of the funal arms deals he was involved with is an Indonesian request to purchase 12 F5 fighter planes, manufactured by the Northrop Corp.

The $86 million F.5 pruchase request is being considered by the State Department, are included in the prices of arms sales as one of the costs of doing business and are treated in a manner similar costs of production.

The fees are not calculated on a percentage basis, but must be "resonable." The task of determining if a fee is reasonable falls to the systems command of the service concerned - which is the Air Force, in the case of the proposed F.5 sale.

According to officials close to the situation, it is immpossible, to determine how large role Grills played in the F.5 negotiations. Dicussions between the United States and Indonesian began in 1971, before Grills got there, but continued for most of his tenure in Jakarta.

The Defence liasion office chiefs position is about fifth or sixt in the U.S. pecking order for Indonesia, officials said, falling below the ambassador and several of his assistants.

Nevertheless, said one official, "there's no question but that they did discuss it" with Grills.

"I don't feel very comfortable with a MAAG [liasion office] chief going to work for a company whose job it is to get its country to buy the things he works with," said a high-ranking officials close to the case "I think it smells."

Northrop officials, while relunctant to discuss Grills' involvement in the F5 proposal ("it's something between him and the Pentagon, not really our business," said one), expressed some concern about his new job.

"We did ask him about it," said a spokesman, "because we wanted to be sure there would be no objection" from the Pentagon.

When he retired, Grills submitted to the Army a statement of intended future employment required of all retiring Army officers. Defence Department officials said the document cannot be released because of the Privacy Act of 1974.

In addition to Northdrop, Karya has represented General Electric Co., Fairchill Industries, Sikorsky Aircraft, Westinghouse, Cadillac Gage Co. and Smith and Wesson, among others, sources said.

Of those companies, the only one that made a large arms sale to Indonesia during Grills' tenure there was Cadillac Gage, which sold Indonesia 45 V.150 armored cars for $7.9 million during fiscal 1975, according to the Pentagon. No information was available on any agent's free paid Karya in that transaction.