Request URI error

Hi all,

I have a problem when I try to call the read method of a new REST service.

This is the definition done for the service:

The problem is, that wenn I use the following request, I get the error below:
String --> http://p2w4r5s8:8080/sap/opu/odata/sap/ZZ_TEST_GATEWAY_002_SRV/ZZZ_ENTITY_002Set(IBUKRS='1',IGpart='1',IVtref='1')
Error ---> <message xml:lang="en">Invalid key name in key predicate. Expected name is 'IBukrs, IGpart, IVtref'</message>

Wenn I use the following request, I get the error below:
String --> http://p2w4r5s8:8080/sap/opu/odata/sap/ZZ_TEST_GATEWAY_002_SRV/ZZZ_ENTITY_002Set(1,1,1)
Error ---> Invalid key predicate

Wenn I use the following request, I get the error below:
String --> http://p2w4r5s8:8080/sap/opu/odata/sap/ZZ_TEST_GATEWAY_002_SRV/ZZZ_ENTITY_002?$filter=IBUKRS eq '1' and IGpart eq '1' and IVtref eq '1'
Error ---> Resource not found for the segment 'ZZZ_ENTITY_002'

How must the request(url) be done to perform the READ and get the data without errors? Or what can I do to solve it? Any idea?

Thanks in advance
mar