mikrotik 750gl +adsl + static ip

Hi,
I have a mikrotik 750gl which I want to put before an adsl modem/router (atlantis 141 WN+) to best manage and shape traffics of some clients.
I specify that I got a set of public IP from my provider and all clients have a public static ip assigned.
I followed this guide
http://wiki.mikrotik.com/wiki/How_to_Connect_your_Home_Network_to_xDSL_Line
But in my case all clients must surf on internet with their own public static IP without masquerading.
so far I could make mikrotik 750gl to connect over PPPoE-client but I couldn’t make clients behind mikrotik to go on internet with their own public ip.
Someone can give me any suggestion to figure out that?
Thanks in advance

How your isp is routing/assigning your ip’s to you?
How many IP adresses you have from ISP?
Are your clients dialing PPPoE connections to you?