Pro Tools LE / Lexicon PCM-91 connection question

[mfretton]

Hi, I'm recording on an analogue open reel set-up, then transferring tracks to Pro Tools LE for finishing work & overdubs. My analogue set-up includes a Lexicon PCM-91 which I'd also like to use with Pro Tools LE but don't know how to set up the equivalent of a send & return from Pro Tools. Please could someone offer some advice about how to connect them?

I have an Mbox 2 but suspect that I may need a different interface in order to do this. I'd be happy to get some sort of control surface, as I'm still pretty old-school when it comes to recording.

All advice, preferably in the most simple terms, gratefully received!

Matt