you need to to turn the cab into a package and then turn that package into an ext, i would atleast put the links, but posting this from my phone, just just search for cab to oem, and oen to ext. there might be something more one step, but this is how i do it, and it works fine, havent been able to find something that can do it in just one step or program. hope this helps. just reply if u need more help with this
http://forum.xda-developers.com/showthread.php?t=469420
that is the link where you can download what you need, bottom of post #1 in the thread. it will take an oem to an ext