Set User-Agent header on REGISTER message generated by HMP WIN

Hello,

   I have a 1PCC application using HMP Windows.  We are interfacing to a PBX which requires that the REGISTER request generated by HMP include a User-Agent header.
I can set a User-Agent header on every other message (using gc_SetUserInfo() as described in section 4.9 of the GlobalCall IP for HMP tTechnology guide), but not the REGISTER messages.  It looks like SetUserInfo() only references a line device, whereas registration is at the board level.

   Is there a way to specify a User-Agent header to be inlcuded in the REGISTER message?

Thanks,

Tony