It is possible to import either HSpice, PSpice or Berkeley Spice netlists into Saber Designer. Depending on the version you use, you may have more or less success. The conversion program is called nspitos, and is basically a Perl script. It could be accessed from PartBrowser-> Tools-> Nspitos.
It should exist in all versions of Saber, and not as a separate plug-in.
Good luck! I would be curious to know the rate of success.
Remark: Saber has as well some native H-Spice models for the transistors. You can choose if you want a mapping to MAST models or to Spice-equivalents.
Regards,
fuller