THis is a bit old but here we go anyway...
So, you'd need to use a MPGW or a XMLFW to be able to receive a HTTP POST of "binary/non-XML" data as DataPower will interpret it as.
Any front-side-handler can use any port on DataPower so a MPGW can too use port 80, 443 or whatever you like.
If you mean that you already have a WSP configured listeneing on 80, 8080 and 443 then you'd need to add a "routing service" in front of the WSP that uses those ports and then rout to either WSP or MPGW depending on the request payload (aka. Service-Chaining).
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Anders Wasén, Sr. Solutions Architect
IBM Champion, IBM DataPower Gateways, IBM Transformation Extender