sync center and offline folders

Hello,

I would like to sync files between my external drive and desktop.
I own vista ultimate.


I tried to use the sync center.
I tried to setup offline folders but could not succeed.

I cannot make folders "offline folders"

In the control panel I have enable offline folders, but still,
when i right click a folder, I do not see the selection 'always available
for offline'
(or a similar messsage).

How do I work with my folders so that they are also offline folders...

I dont get the idea in general and I dont know how to work with it.