Microsoft has formally answered a request from the European Commission on the powers an independent trustee would have to monitor the company's compliance with conditions laid down in the antitrust ruling against the firm.

The Commission, which is the EU's antitrust regulator, told Microsoft on 2 April that its proposal on the "monitoring trustee" amounted to a veto over which issues the trustee could examine. The monitoring trustee is an independent person whose appointment must be agreed to by both sides.

The Commission said this "veto" would be unacceptable because it would compromise the trustee's ability to provide the Commission with assistance in monitoring how Microsoft complied with the antitrust ruling.

The EU's antitrust regulator gave the company 10 days to respond to its objections, warning that unless Microsoft agreed with the Commission proposal on monitoring it would impose it on the firm.

Under the terms of the March 2004 ruling by the Commission against Microsoft, the company was ordered to offer a version of its Windows PC operating system without Media Player, ensure interoperability with its workgroup server technology by granting access to communications protocols under fair licensing terms and pay a fine of €497m.

One of the aspects of the Commission's ruling was that the company should accept the appointment of a "monitoring trustee" to oversee compliance with the ruling in the future.

In negotiations over exactly how it will comply with the ruling, Microsoft has agreed to call the unbundled version of Windows "XP N." The Commission is still unhappy with the terms the company is offering on licensing its communications protocols for workgroup servers.

The Commission is currently collecting responses from other players in the market, including some of Microsoft's rivals that brought the initial complaint, on how the company is planning to comply with the ruling.

The antitrust regulator is expected to start publicising its view of whether Microsoft's offers in a number of areas are acceptable toward the end of next week.