[Gvsig_english] how to move a polygon vertex to assigned coordinates

[G. Allegri]

Hello eveyone.
I'm wondering if Gvsig lets you define manually (like CAD) the
destination coordinates of a vertex while editing a polygon. I've
tried to use the "Edit vertex" tool, but its command line is not clear
to me. It seems I can just move around the vertexes order, delete one,
add one clicking in a point on the polygon boundary...

So I can't do the two following things:

 - as  I said, set manually the destination coords for a vertex, or
set a new vertex also manually
 - graphically create a new polygon vertex outside of the polygon
boundary. I mean, I would like not to have to add a vertex and then
switch to another tool to move it to its final location, like it seems
the only way now to me...

Anyway, the first task is the most important to me, as I have a set of
vertexes coordinates I have to modify manually...

thanks a lot!
giovanni