Looking for help with PNG prob in Visio

[BigTeeJay]

Greetings all,
I am looking for some place to target this request
for help, but I havent had much luck (looked for
something on the PNG page too...) If anyone has
an idea of a better place/person to send this
question to, I would appreciate it.

In the even that any of you know the answer, I will
post my question (couldnt hurt right?)

When I export/'save as' a shape in Visio to GIF, the
pict that is produced looks just like the original
does in Visio. But if I try to export it as PNG,
the colors arent always coming out (it also seems to
depend on how many other colors there are). Additionally
some I set a shadow for an object, and it wasnt being
reproduced in the PNG, but when I created a shape of
the same color and same shape as the shadow, it came
out fine.

Also, I am using the same transparency settings for
both (background color, and transparency color) but
the PNG doesnt end up with a transparent background
(while the GIF works fine).

Any ideas?

TIA