Your on the right track IMO.

Many OS keep there sendmail program in different places,
in these situations it is common to find that the OS provide their own packages for the Perl Modules:
like here for Mandrake (as one for instance).
In these situations it is better to forsake perl -MCPAN -e 'shell' for RPMs in your case.

Alternatively you could use symlinks to cobble a solution.

--

Brother Frankus.

¤