The Internal Revenue Service is advising the nonprofit employers that have to comply with new written-plan requirements not worry about the current lack of formal compliance guidelines.

Schools and other plan sponsors that do their best to comply with the requirements will have time to make changes once the final rules come out, IRS officials say in Announcement 2009-89.

The IRS is in the process of implementing laws that require 403(b) plan sponsors to adopt formal plan documents by the end of 2009. The IRS has published a model showing generally what the written documents should look like, in Revenue Procedure 2007-71.

But the IRS has not yet explained how the financial services companies that develop preapproved prototype plans can get IRS opinion letters stating that the 403(b) prototype plans meet IRS requirements, or how employers can get determination letters stating that individual 403(b) plans conform.

The IRS hopes to publish revenue procedures explaining the 403(b) opinion letter and determination letter processes soon.

If an employer establishes a plan using model language given in IRS Revenue Procedure 2007-71, then adopts a preapproved plan or gets an IRS determination letter letter once those are available, “the employer will have a remedial amendment period in which to amend the plan to correct any form defects retroactive to January 1, 2010,” IRS officials say in the announcement.

An employer that adopts a preapproved plan retroactive to Jan. 1, 2010, or changes the plan to correct any defects retroactively, will have a plan that meets IRS 403(b) written document requirements as of Jan. 1, 2010, officials say.

The upcoming revenue procedures will explain how sponsors can fix their plans, and how the companies that offer preapproved plans can fixed the preapproved plans, officials say.

“Accordingly, employers should not request ruling or determination letters on the form of their Section 403(b) plans at this time, pending publication of the revenue procedure for pre-approved Section 403(b) plans and additional procedures on applying for individual determination letters for section 403(b) plans,” officials say.

A copy of the IRS announcement is available here.