Send an internal source through remote proxy

[jg3]

Hi, first post – please be gentle. (:

I have a single host on my network and I want to send all traffic originating with this host out to be proxied through a remote system on the Internet (not a gateway within the same subnet as my WAN link default GW).  How can I accomplish this in pfsense?

I am running 2.0.1-Release.  I have a very simple set-up, two NICs: one WAN one LAN.  WAN connects directly to ISP, LAN connects to internal network and serves DHCP and DNS.  Internally the network is a flat /24.

And no, the internal system doesn't have a proxy setting.  (:

I am comfortable with basic networking and routing, but I'm not sure how this is presented in the pfSense interface; I am very new to pfSense.

Thanks for any pointers.