From what I've discovered so far, the RPMs downloaded from the web repositories are saved here:
/var/adm/YaST/InstSrcManager
There are various folders, such as: IS_CACHE_0x00000001

What I want to do is learn how to keep this RPM files (even after I reboot), so that I can later enable a network (SMB based repositories).
We want to use SuSE Linux in 2 machines, and I want one machine to be a gateway, in which all the repositories should be saved (like in Ubuntu, where everything is saved at /var/cache/apt/archives/ )

I've google this problem for an hour or so without any luck, I'll appreciate any help

if you're not concerned with directory structure run something like

cp -r /var/adm/YaST/InstSrcManager/ /folder/you/specify

then you can always weed through it later