How to wake up other computer in Homegroup

I have two win 7 machines configured in my Homegroup on a Home wireless network. One is a netbook connected wirelessly to my router, and my main desktop us plugged directly into the router. They work fine when they are both awake, but neither of them seems to be able to wake each other up once they go to sleep. Wake on LAN is enabled on both of them using magic packet only. I want to avoid disabling magic packet so my main machine doesn't keep waking up all the time.

I also verified HomeGroupListener and HomeGroupProvider services are running. Is this likely my router blocking something and preventing them from waking each other up, or is there something else I need to configure? Very frustrating b/c I often need to hit files on my main desktop from my netbook pc downstairs. My understanding is that if WOL is enabled, computers in the homegroup should wake each other up when trying to access files on the other machine. I really want to get it to work and not have to mess around with tools or command line to manually wake them up. Any help is appreciated. Thanks.

Update on this. I was actually looking at this more closely and it may not really be a WOL type issue. my main desktop (64 bit Win7 Home Premium) can see and access files on my netbook (win 7 Starter 32bit) using HomeGroup.

However, my netbook is unable to see my main PC or access any files via homegroup. The netbook is able to see and access files on my main PC using the normal Network portion of Win7, just not via HomeGroup. This is something specific to Homegroup. Do I need to try that registry update to enable IPv6? I saw another thread about that. Don't want to mess with that if it won't fix this problem. Thanks.

I started doing all kinds of crazy stuff determined to get this figured out. I think I might have stumbled onto a bug here. I got it to work by specifically going into the library via explorer, right clicking on the specific library (Pictures, documents, etc) and then selecting share (read/write).

Selecting the library sharing permissions using the checkbox method from the main HomeGroup configuration screen was not working. As soon as I did that, the libraries began showing up one by one on my netbook. very strange.