Sleep mode not happy with WiFi

I was kind of used to use Sleep mode on my Tablet PC since I want fast wakeup whenever I want to use my machine. But then I realized that when my Tablet PC is awaken from sleep mode, the WiFi WILL NOT WORK. And I have to reboot the machine. That's kind of suck and I don't know if I should blame the Lenovo (the maker of my laptop) or blame Vista.

Suddenly Asus PC Eee seems even more appealing than ever...