Migrating with mixed envIS 61 and ES 501 can I use WmEnterprise Package

We have successfully bought up IS 6.1 and ES 5.0.1 on a test machine. Numerous projects make use of the WmEnterprise package and the B2B Service Package adapter. I was under impression that I would have to change integrations and services that communication between the two, to use the new pub.publish:publish service (and triggers too).

However, I decided to start up a B2BServicePackage adapter, pointing to IS 6.1. It started with no problems. This got me to thinking, maybe I don’t need to modify all the existing service and integrations until I migrate them fully to IS 6.1. I’d just need to do a WmEnterpise installation on IS 6.1.

Think this will work?