Vista - BITS problem under limited account

I'm looking at the possibility of using the BITS (Background Intelligent Transfer Service) to implement an Auto-Update app. It is used by Windows Update, and APIs are available for any application to use it as well.
But the bad thing with BITS is that it fails if you aren't logged on as an administrator. RunAs under limited account always fails with an error (a generic error (NOT LOGGED ON) that doesn't accurately describe the situation).

Is something else I can do to make it work under limited account? I appreciate.