As far as I know, if the dynamic process is part of the XC, you cannot use property or method owned by the XControl itself.
More than a long text in a "crappy" english, I've attached a quick sample code (apologize for the messy G code, but it works) demonstrating what I've understood from your need.
open the xctl file
drop it in the New VI Front panel
click on "Load // process" button
send message from window to Xcontrol
Let me know if it helps you.
Regards
XC.zip