> SEQUENTIAL = GEN_ID("GEN_KIND_" || ID_KIND, 1);

Sorry Enio, this is simply impossible. A Stored Procedure has to be
"precompiled" and dynamic access like this is not covered. What I suggest
you do, is to go to http://www.ibobjects.com/TechInfo.html and download the
article "An Auditable Series of Numbers" to see if it contains any
information you can use.

HTH,
Set