This is a new version of callback.dll for CTD. The callback functions now return values from the associated CTD functions. The number of available callback handlers has been increased to 3 (available via SetCallback2 and SetCallback3).
For further information and samples have a look at my website at:

http://www.cschubert.net/html/callback.html

Have fun.

Christian Schubert
christian@cschubert.net