Litespeed alongside Apache and Plesk? (for Rails)

[subBlue]

We are currently running 15 rails based sites on an apache 2 server, which is managed by Plesk 8.01 (on Centos 4.2). Apache and fast_cgi seems to be starting to strain at the seems so I'm evaluating other options and Litespeed looks very interesting.

The Plesk control panel has a different IP address (and runs on a different port) on the server from the websites (and a couple of the websites have unique IPs as they have SSL certificates).
My question is whether it would be possible to use Litespeed for all our Rails sites but keep apache for the server management with Plesk? If so what would be the approach for this in configuring my current Apache and litespeed? Would it also be possible to test it on one IP range first?

Many thanks
Tom