Have you tried installing it with PPM? Apparently, a PPM package is available: Net::SSH::Perl — but I see no reason not to install Net::SSH instead (if it is compatible).

And yes, Strawberry Perl can install PPM packages, it has its own PPM command line program — not the same as ActiveState's, but it works.

You may have to add at least one of the repositories where it can be found to its repository list, first.