To answer my own question - 
Yes, it's described in the help for the rs-232 library - use ComSetEscape 

BUT - some, if not a lot, of the semantics of this function depend upon the serial driver being used.  So, for example, if I'm using a plain vanilla Windows 32 bit serial driver from, say Win2K or WinXP, how in the world do I figure out what the driver supports?  And if I'm using the NI serial driver, how do I figure out which escape codes it supports?
Thanks.
Menchar