There are some solutions to your problem. I'm employing, nowadays, STARTD variables that I can put in the submit files, for example:
Add to HTCondor configuration (execute nodes):
EXECUTABLE_PATH = "c:\xpto\asd.exe"
STARTD_ATTRS = $(STARTD_ATTRS), EXECUTABLE_PATH
And you'll be able to put, on the submit file:
executable = $$(EXECUTABLE_PATH)
Var will be resolved on executing machine. As I said, this is only one way to address the problem, but it works.