That would most likely be because of the way you activated your USB.
Are you using GenericUSBXHCI.kext? Or the native apple drivers.
Reply with the wake-up reason from /var/log/system.log
I'm not using the GenricUSBXHCI.kext because when I tried it, my computer freeze every time I plugged a usb storage stick. Right now I'm using just the native apple drivers.
here are my wake up logs so you can see how of ten it wakes up by itself:
Dec 30 04:44:02 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:45:06 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:46:10 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:47:13 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:48:17 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:49:22 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:50:27 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:51:31 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:52:35 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:53:40 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:54:44 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:55:49 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:56:54 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:57:57 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 04:59:02 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:00:05 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:01:09 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:02:12 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:03:16 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:04:20 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:05:17 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:06:27 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:07:30 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 05:08:34 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 08:54:59 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 19:01:02 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 19:11:09 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 19:39:51 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 19:55:50 iMac kernel[0] <Notice>: Wake reason: XHC1
Dec 30 20:04:28 iMac kernel[0] <Notice>: Wake reason: XHC1
Any help will be really appreciated since I had to uninstall the BrcmPatchRAM to avoid the wake up issue and now the magic mouse and apple wireless keyboard not always works like they used with your patch.
Here are my logs after uninstalling the patch (Note that all those wakes were induced and not automatically)
Dec 31 19:33:19 iMac kernel[0] <Notice>: Wake reason: XHC
Jan 1 12:01:56 iMac kernel[0] <Notice>: Wake reason: XHC
Jan 1 13:18:31 iMac kernel[0] <Notice>: Wake reason: XHC
Jan 1 13:20:08 iMac kernel[0] <Notice>: Wake reason: XHC
Jan 1 14:38:40 iMac kernel[0] <Notice>: Wake reason: XHC