Truth Told:
1. What are SoundFonts?
SoundFonts are merely wave-form samples (.wav files) that have been treated and transformed by a SoundFont editor into MIDI-controllable instruments which can be loaded onto your soundcard and used by your sequencer. Several wave samples (one for each pitch or group of pitches) form an instrument. One or more instruments are grouped into banks. Each instrument in a bank has an ID number which is called program number or patch number. SoundFont Banks (files with .sf2 extension) can contain definitions of from 1 to 128 instruments and 1 drum set.
2. as far as i know, SampleTank DOESN'T support soundfonts. please recheck...
i might be wrong, as i've never used SampleTank, but i've read heaps about it...