Hi David,
It sounds like you are already using HEAT to it's full extent - as in - the ADS/EVM has to be the one to send or request the data as far as I'm aware (in it's standard usage).
I believe the Visual C++ source for the HEAT server is provided with SDOS, so if the user wishes to modify this - that could be done, but this isn't supported by Freescale.
-Andrew