Well I looked around for a RPM you suggested, but couldn't find any

.
I tried compiling the OpenSSL 0.9.8a from the sources, and that DID install the shared libraries I needed (libssl.so.0.9.8 and libcrypto.so.0.9.8) but that didn't actually solve my problem. When I try to install a RPM that needs OpenSSL 0.9.8 it can't find the .so-s from the 0.9.8 version, because these file aren't in the RPMs database.
What I did was to forcedly install the new version:
"rpm -ivh openssl.0.9.8a-13.i586.rpm"
Now this isn't a real solution, because it overwrote some files of the old 0.9.7 version, but seems to work for the moment. I guess I still can revert to the old version by forcedly re-installing the old version
What probably should have been done is to recompile all of the apps that need the old libraries, so that they're linked with the new version of the libs. Kind of annoying, I won't do that, it would be easier to switch to the new version of the whole distribution.