0. In cwm (make sure you have 126.96.36.199 or higher, install it via rommanger from market) navigate to
1. flash cm7kang-O2x-P204-27
2. flash gapps-gb-20111214-237-signed
3. flash ironkernelPSUV
PS: Make sure you have the right baseband/ril combination. Officially CM7 for O2X is based on BB218. If you are on Stock 2.2.2 with that baseband, then you do not need to do anything. If you are on Stock 2.3.4 with BB725, make sure you install froyo
725ril via 'getril'-app from market. All in all, BB218 is recommended.