Check in Preferences under MIDI/MIDI File/Import Options/Destination that it is set to “MIDI Tracks” and that “Auto-dissolve Format 0” is selected, that should load into individual tracks. XG files will have the correct Program Change embedded in each track. Set the output of each track to your VSTi.
Pity you don’t still have the DB50XG … it can be adapted to be an external MIDI expander with circuits like this. It’s also possible to fit into the box of the Terratec DMX 6-Fire, an older PCI soundcard and the built-in synth in the Axon AX 100 is actually on a Waveblaster connector, so it’s just a matter of exchanging it for a DB50XG.
I hadn’t come across the S-YXG50 before, but I’d say it’s pretty old software and I’m assuming it’s only 32-bit, so I wouldn’t care to test its stability on Windows 7 or 8 64-bit.