Single sign-on authentication failure with Citrix PNAgent

[kiros]

I am trying to get pass-through (Single sign-on authentication) to
work with the Citrix PNAgent client version 8.1 on XP Ombedded thin
client. It can work successfully on an XP Pro machine.
But XPE to the same servers, using the same accounts, always
prompts for credentials.

Any anyone successfully gotten PNAgent working on XPE?
Is it probably a missing component?

Thanks!

Kiros