Can you give me anything that state Exchange schema isn't supported on AD LDS? Or do you have any idea why MS do not support this? Actually I just need to have user class exactly the same on AD. (with all attributes)
The Exchange schema makes assumptions on AD DS that can't be satisfied on AD LDS. There is no explicit documentation that states that it's not supported, but I'm pretty sure that it is neither technically possible or supported, but only Microsoft can give you a definitive state of support, I do not work for Microsoft.
You might can use the ADLDS Schema Analyzer Tool to export enough attributes to full fill your needs:
http://blogs.technet.com/b/askds/archive/2009/01/20/determine-applied-schema-extensions-with-ad-ds-lds-schema-analyzer.aspx
Enfo Zipper
Christoffer Andersson – Principal Advisor
http://blogs.chrisse.se - Directory Services Blog