Hi "vmudila",
Generally you can not launch APPL from an UBE, because there "Run Executable" system function end Form Interconnect is not available - as far as I know on all SP level.
Maybe you can do it somehow writing your own C BSFN to launch APPL.
On the other hand:
Q1.) Why do you want it to do?
Q2.) What is your platform and system configuration?
Regards,
Zoltán