Routing and NAT

Hi, We have just recently started looking at using MikroTik kit because of some of the features. The main one being built in PPPoE server and bandwidth control per session.
We are currently using Draytek routers at one of our larger sites and I’m trying to emulate what the Draytek is doing but use some of the nice additions that the MikroTik has to offer.
What we currently have is this:
A WAN connection with multiple public IP’s provided via ethernet from our ISP
This is connected to the Draytek (call this Draytek ‘A’) WAN port.
Draytek ‘A’ takes a public IP for itself and uses this address for NAT to the internal clients
We also have the ‘routed subnet’ option switched on. This uses another Public IP on Draytek ‘A’.
We have another Draytek (Draytek ‘B’),on the network which has been set up to use one of the other Public IP’s with the second public IP on Draytek ‘A’ as its gateway.
Its WAN port is connected to the LAN side of Draytek ‘A’
Draytek ‘B’ is reachable from the internet via Draytek ‘A’ with no NAT taking place, so I assume fully routed.

I want to achieve the same thing using the MikroTik in place of Draytek ‘A’ but using PPPoE.
What I have achieved so far is configuring the PPPoE server, have it hand out internal addresses that are NAT’d through the MikroTik’s WAN port.
What I can’t seem to get to work (I’m probably doing it completely wrong, the Draytek has a nice fuzzy click and go setup) is having a Public IP handed to a PPPoE client and have it access the internet without any NATing taking place. As well as being able to access that cllient from the WAN.

Could anyone help me out or give me some pointers?