individual 401(k) in partnership

In a sole proprietorship, profit sharing contributions to an individual 401(k) (or SEP) can be 20% of the net profits of the business (hold back 20% for profit sharing, pay the owner 80%, and then the 20% held back is 25% of remaining profits - the legal max for contributions to the 401(k)). Does it work the same way for partnerships, where the partners may have guaranteed payments ("salary") as well as drawing profits from the business? Or is one limited to 25% of the profits after subtracting off the guaranteed payments (unlike the sole proprietorship)? Related question - if one is an owner/partner in two businesses, what is the interplay between profit sharing contributions of the two businesses? Is is as simple as following the rules for max profit sharing for each business, subject to the section 415 limit of $45,000 total for an individual (2007)? Or is it more complex than that? Thanks, Mark Freeland snipped-for-privacy@sbcglobal.net