Actually you would just need to replace the images in MsgPlusLiveRes.dll
To do this you can use res hack
The things that you need to replace are:
PNG > IMG_BUDDY-BLOCKED-OFFLINE > 0
PNG > IMG_BUDDY-OFFLINE > 0
Only bad this is that you shouldnt replace things like this (I dunno if patchou would like it or not...) and also you need the 2 images
also: I haven't tested this but it should work is theory