Actaully, I dont think that the force roam option will be there in 1.2 due to Sprints crack dwon on roaming anyway. Just something that I heard may not be true.
However, there is an easier way to do this without rooting your phone if you dont feel all warm and comfy inside doing so. Just download webOS Install and the option is there under tweaks. But remember it is highly recommended to undo any tweak that you apply here or by any other means will need to be removed BEFORE you upgrade to 1.2 when it is released.
http://forums.precentral.net/homebre...k-install.html