This is something I've been hoping would be added for some time. HTTrack is a
great app but it's inability to do this very well is quite limiting. We have
this functionality built-in to our home brew spider but there are many things
that HTTrack does better so I'd like to go forward using it. 

It should be fairly simple to add. All you need to do is a http post instead
of an http get, and then specify the name/value pairs of the form you'd like
to post to accompanied by a URL. 

Please add this.