Does anyone have an S-Control  or Formula that will take a start date and add a duration in months to calculate an end date?

I've tried handling this in SF itself through a workflow rule trigger by breaking out the dates into MM DD Year fields and manipulating that way.  The problem is of course Validating the end date is a true since the current work around causes a problem.  ie: Jan 31 2007 + 1 Month = Feb 31, 2007 ... not a valid date.

Since we have Admin Support SF personnel tried to write a formula for the calculation and after a few weeks gave up and told me the only way to handle this is with a Custom S-Control.

Any suggestions / help would be appreciated.

Thanks

AGM