ICS 4.0.3 back to GB 2.3.4 and keeping root

I have my S2 rooted running Resurrection Remix Pro v1.1
Baseband i9100ZSLPE
Android Vers 4.0.3
Kernel version 3.0.15-i9100DXLP7-CL233393 dpi@DELL166#3

However, I cant get SkyGo to run as it is not compatible with ICS.

I have downloaded the following rom: I9100XWKI4_I9100XEUKH2_EUK.zip
It contains the file : I9100XWKI4_I9100XEUKH2_I9100XXKI1_HOME.tar.md5
Can I install this using ClockWorkMod in recovery mode, or do I have to use Odin??

The reason I ask is that Voodoo Rootkeeper apparently does not work with phones updated with Odin, therefore if I can update using the zip file and CWM, that would be better for me as I will be able to root or unroot as required.