I'm certain that REXX has an includable library to handle any supported dataset format for that platform. You just have to indentify the library.
Some looking reveals a way to use a tempfile and EXECIO for VSAM access without a library, and that the library needed is RXVSAM:
[link|http://mywebpages.comcast.net/gsf/tools/tsovsam.html|http://mywebpages.co...ools/tsovsam.html]
The advantages of REXX over COBOL, particularly for a Perler, make dealing with these headaches worth it, IMO.