I have been using the ShapeDesigner sample to create custom shapes to use in my software.
Unfortunately it does not appear possible to create shapes of differing height and width.
After searching the forums here I came across a thread from 2007 that stated that this was indeed not possible and offered the source code to the ShapeDesigner to allow the poster to make the alterations himself.
Seeing that the sourcecode posted in that thread is outdated, I was wondering if
a) creating non-square shapes is now inherently supported and I just missed it
or
b) an updated version of the sourcecode is available to make the necessary changes myself?

If you create a shape in the shape editor that is twice as wide as it is high (a rectangle that only covers the upper half of the grid, for example) and apply this shape to a node, only the node's upper half will be visible (because, as you say, the shape gets scaled to the node's size).
Handles, Anchor Points etc. still refer to the node's bounds though, meaning that connections attach to the node at a point that (for the user) appears to be some distance away from it.
So, fitting a 100x100 shape into a 100x50 node works fine, but fitting a 100x50 shape into any node does not, since MindFusion appearantly considers all shapes to be square, so my 100x50 shape is actually a 100x100 shape, just with the bottom half left empty.
I could of course design the shapes to be 100x100 and apply them to 100x50 nodes, but since the symbols I am trying to represent in the shapes contain text, this would lead to them looking warped unless I somehow managed to design them at a precise 2:1 vertical scale.

I think I'll just go with pictures of each symbol on default rectangular nodes and adjust the bounds according to the size of the images.
Thank you for taking the time to clear this up.