No, I don't think you'll need to do the HFA.
Since you've got management on the box, it makes it more of a pain. Make sure you have a good backup before starting.
That said, I think the steps will be something like this:
* Upgrade IPSO first (I would go to 4.1 personally)
* The upgrade will probably deactivate the package. I think you need to reactivate it, then install the R61 package, but install it as an upgrade.
From the command line, it will be something like:
newpkg -m LOCAL -n <pkg_name> -o $FWDIR
The -o $FWDIR tells it to do an upgrade.
But read through the release notes carefully before doing it. Read the release notes for both IPSO and R61.