Glissandos with (de)crescendos

Is it just me or shouldn't this:

a glissando between two half notes with a decrescendo (I had the velocity be 100 units of change)
actually effect the glissando's playback? It doesn't over here. It would be nice to have the glissando
be affected as it played with a de/crescendo.
...
Also: only the velocity change of the first note is what affects the glissando. This means that I can't
have the first note played at FForte and then have the glissando playback as P. Am I missing some-
thing? Please help if you know how to do this. Otherwise I'd have to create an extra note with a velo-
city change in the middle of it, and this looks muddy compared to a slick two note chromatic
glissando. I was thinking maybe the glissando ought to have its own velocity quality like a notehead
does, let alone getting it to follow a crescendo/decrescendo. Thanks for any feedback.