Paul,
As has been noted, OBJ files are architecture specific. So, the code will need to be recompiled.
If the codebase is old, I generally recommend that clients recompile (and verify that the code recompiles correctly and runs correctly) on Alpha; then recompile and test on Itanium.
Your mileage (or kilometerage) may vary, but well written build procedures often work with no problem.
Recompilation is the preferred route, however, image translation is useful tool for transitioning large code bases.
Some comments on this are contained in my OpenVMS Technical Journal article, "Strategies for Migrating from Alpha and VAX systems to HP Integrity Servers on OpenVMS" (Volume 10, June 2007). An abstract of that article, together with a link to the complete article, can be found at:
http://www.rlgsc.com/publications/vmstechjournal/migrationstrategies.html- Bob Gezelter,
http://www.rlgsc.com