Patching a Solaris flar archive

I have a Solaris flar archive of an old Solaris 10 environment, now I'm not allowed to update the running system in any way so would like to be able to: 1. Extract the flar archive somewhere (without installing it) 2. Apply some Solaris patches to the extracted archive. 3. Repackage the flar archive 4. Use the flar archive to setup a branded zone. Why do it this way? Well because I need a set of minimum patches to get the darned thing to work as a branded zone. I know how to do step 4 if I ever get to it.