As TomG said the processors within the Synology NAS range are not compatible with VMWare. I believe VMWare requires a CPU with built in Virtualization Technology (VT-x).
This can be found in most desktop/laptop machines for example Intel Core Duo or Centrino Duo etc... But not within the PPC CPU's in most modern Synology machines.
The latest Synology models DS710+ etc. DO have Intel chips BUT their Atom processors do not include VT technology. So I don't think you'll be using a Synology for running a vm for
a while yet!
However, you can run VMWare Server on your laptop/desktop and reference the Synology storage.
To give you an idea of the level of specification you might use, I have a Sony Laptop, 3 years old (Intel Core2 Duo T7500 [2.2GHz]) machine with 4Gig RAM connected to a Synology DS209+ via
gigabit ethernet (wired don't entertain wireless it'll end up in tears).
Which runs Windows 7 [64bit] and VMWare Server ver 2.0.
I am able to run multiple vm's located on the Synology but running on the Laptop's CPU, no problems.
Hope this helps, good luck.