Soundfont problem

Greetings gang.

I've noticed an odd thing about my SoundBlaster Live! and I was wondering if
this is some sort of internal defect peculiar to my own card, of if this is
a problem everyone else has.

System Specifics:
O/S: Windows XP Professional Service Pack 2 (Slipstreamed before installing,
this is not an "upgrade").
System: Dual Pentium III mobo at 933 MHz
RAM: 512 Mb
Audio: SoundBlaster Live!
SoundFont: "25.5 MB GeneralUser GS 1.1 Bank (Live! ver.).sf2"

I key in an "open high hat" note [Bb3, channel 10] in a MIDI editor (I use
PowerTracks Pro 9) followed by the "closed high hat" note [F#3] or the "foot
pedal closed" note [Ab3]. If the volume of the "open high hat" note is set
at 100 of 127 or lower the "closed high hat" note or the "foot pedal closed"
note will kill (appropriately) the sound of the ringing open high hat.
However, if I adjust the open high hat note [Bb3] volume anywhere between
101 and 127 the closed note following it has no effect in shutting of the
original note.

I should also mention that this is true of open high hat notes that play in
any player, not just PowerTracks. The Windows Media Player will produce the
same thing when I play a default file from C:\Windows\Media such as
"flourish.mid".

Now, I've tested other soundfonts. I don't get the same results. When set to
a volume of 127 the second note will clear the first. So all is well.

Is this a problem I can repair via Vienna? Any ideas?

Thanks.