Mixed authentication

I am considering FileUltimate. I would like to be able to authenticate against Active Directory and also a list of FileUltimate users. Active directory would be tried first, I suppose. Also, setting access permission for either type of account would be needed.

The reason is that we have mostly Active Directory users, but there are times we need to share files with outside consultants.

Is this possible with either the out-of-the-box version or the source code version? I am an ASP.Net developer.

Thanks.

Anyone? Bueller?