Hi Kai
There is no need for that. Ideally even NW 731 should have the same ODATA features. Can you check if the ODATA SCA is deployed on your NW server? From the error message above it seems it is there but to double check.
Also in line with Pedro's comment above I checked the help for ODATA. You can find it here. http://help.sap.com/saphelp_mii140/helpdata/en/44/2e1d2d42994aef85ef91e58db8c7c9/frameset.htm
MII ODATA Does support FixedQueryWithOutput but only with HTTP method set as POST and not GET. You may try this as well. All other modes are supported both with GET as well as POST.
Regards
Partha