Unix and Windows Kerberos Application

[pgrojean@comcast.net]

I noticed that the MIT distribution contains only:
     Windows sources and binaries,
     Solaris binaries,
     and recently linux-gnu binaries.

I have a Kerberos application running on multiple platforms:
      HP-UX
      Sun Solaris
      IBM-AIX
      Linux
      Windows NT-XP

I would like to build a Kerberos ‘application server’ for all of the 
above platforms using MIT GSS-API open source.The Kerberos KGC use 
Microsoft Active Directory.

1)How portable is the MIT ‘application server’ code over the above 
mentioned platforms?
- How much I may have to touch the MIT code? Which release to use?

2)Do you think that, instead of building MIT libraries, I should use the 
GSS-API binaries libraries found as part of the OS on each platform, and 
adapt my application for each platform?
- Differences between UNIX Kerberos and Microsoft SSPI Kerberos?