Make Vds to revert to snapshot

Hello, i think this thing are hard to make..

I am using vmware to make vds (virtual machine)..

Running windows xp on vmware, tried to search any key combination of vwmare commands, my script is running on virtual machine, i am thinking how can i do make automaticly revert to snapshot.. Actually doing it manually it is very easy to revert to snapshot.. But not from Virtual machine, maybe anyone have an idea which could help me find a solution for this problem?