Dual WAN router with ADSL modem/router?

I've bought an Edimax BR-6524K dual-WAN router, and was wondering if anyone could advise me on how to set it up with my ADSL modem router (I aim to use it in conjunction with 2 ADSL connections - the 2nd is being installed in the next few weeks).

I currently have an account with Zen Internet - wth a static IP address - and use an Origo modem router. The Edimax router seems to be geared towards non-UK markets, and does not have an option for PPoA connections, so I was wondering how I should configure the WAN port on the Edimax to work with the Origo modem router?

The available "broadband types" for the WAN ports on the Edimax are:
- Cable modem - your ISP will automatically give you an IP address
- Fixed IP xDSL - your ISP has given you an IP address already
- PPPoE - your ISP requires you to use a point-to-point protocol over ethernet connection
- PPTP - your ISP requires you to use a point-to-point tunnelling protocol connection
- L2TP - your ISP requires you to use a layer 2 tunnelling protocol connection
- Telstra Big Pond - for Australia

Presumably I can't use the Edimax to initiate the connection to Zen ADSL, so I'll need to continue to use the Origo to do this, but when I plug the Origo into the WAN port of the Edimax which of the above broadband types should I select?

If you want to leave the origo as it is ie router mode you will be effectively double natting your connection. I believe that the Origo's have a 1/2 bridge mode where it will pass it external ip to a device connected to it (the Origo still does all the authentication with your ISP etc), either way you want cable mode or alternatively you could put the wan port of the Edimax into the DMZ of the Origo, this way although it has an internal ip eg 10.x.x.x or 192.x.x.x it will get all packets forwarded to it.
Half bridge would be the way to go however it normally only really works with a pc connecting routers can be hit or miss.
A good place to ask the question would be Router Tech it's a dedicated Origo site and the chaps there are pretty helpful.

Thanks - have followed this up at router tech. Am keen to know more about the half/full bridging and NATing issues.