The EXCI client supports an optional user exit named DFHXCURM, as defined by the IBM EXCI documentation. You can write a module that implements this exit and configure the EXCI client layer to load and call it. (The exit program can be written in any .NET language, but because the interface is defined as a COBOL group item, additional work is required to implement it in any language other than COBOL.)
The EXCI user exit receives certain parameters regarding each client request, and has the option of changing the APPLID that identifies the target region before the request is made. This has two main uses:
A sample DFHXCURM user exit is included with Enterprise Server for .NET.