Использование перенаправления папки GPO и офлайновые файлы и папки
Xvnc определенно поддерживается на Солярисе и даже связывается недавними выпусками: http://docs.oracle.com/cd/E19253-01/817-0547/gghpo/index.html#6mgbdbssf
Why would you map a drive to the same folder that their My Documents is being redirected to? That makes no sense to me. Their My Documents folder is redirected to a network share, so when they open, create and save from and to their My Documents folder it's opened, created and saved from and to the network share. Why would you need or want a mapped drive to the same share?
You're making it too complicated. Use Folder Redirection for the My Documents folder in combination with Offline Files. Nothing else need be done. When they log on to computerA they access their My Documents from the redirected folder, create, edit and save a document, then log on to computerB and voila! the document they created from computer A is there... of course.
With Offline Files enabled for the redirected My Documents folder anything they do in My Documents while disconnected from the network will be synced when they reconnect.
When in doubt, read the documentation. Best practice is to use a group policy. Don't use a logon script if at all possible. They're a pain to troubleshoot.