hi ricco,
working with CARIS HIPS and SIPS everyday, I can tell you wont be able to process sonar data with EasyView. This program is intended to view datasets done with other software like HIPS and SIPS, ArcGIS Fledermaus and the like. Those are professionnal software and are sold at high price.
I was told people were able to make bathymetric map from HB 3D unit using the free software MB System (
http://www.ldeo.columbia.edu/res/pi/MB-System/) but it demand some Linux skills and serious hydrographic knowledge.
I'm trying to do it as well and my major issue now is to convert *.SON files into someting more popular like *.xtf (with bathymetry packets, not sidescan).
wish this could help.