Try Transformer Reboot to Recovery in the Play Store. I would post the link, but I haven't even posted 8 times at XDA.
The app should make it pop up into recovery when you select "reboot to recovery". It does need root. It's the easiest way. I was having problems getting in to Recovery. I also used GNUFabio's app to install recovery. It was the only thing that would work. This is probably posted above. If so, apologies.
*Oh, and I restored to stock ICS via NVFlash and Vipermod still works to root.