Windchill WRS API - Can't add attributes to WTParts on creation

[TM_10200690]

How can I add data to our custom attributes via the WRS API? We have an attribute for WTParts called "CAT_CODE" and I want to add data to it via the CreatePart command (http://##.###.#.##:##/Windchill/servlet/odata/v5/ProdMgmt/Parts). My data is:

{
    "DefaultUnit":{},
    "EndItem":False,
    "GatheringPart":False,
    "DefaultTraceCode":{},
    "PhantomManufacturingPart":False,
    "ConfigurableModule":{},
    "Name":"pyapitest",
    "Source":{},
    "AssemblyMode":{},
    "Uses@odata.bind":[],
    "DescribedBy@odata.bind":[],
    "References@odata.bind":[],
    "PartDocAssociations@odata.bind":[],
    "Context@odata.bind":"Containers('OR:wt.pdmlink.PDMLinkProduct:109352')",
    "Folder@odata.bind":"Containers('OR:wt.folder.SubFolder:155247')",
    "CAT_CODE": "52",
}

The error code I get when running the POST command is

{"error":{"code":null,"message":"'CAT_CODE' can not be mapped as a property or an annotation."}}

[TM_10200690 · Accepted solution]

Ok, I had a couple issues with the data. The corrected data is:

{
    "DefaultUnit":{},
    "EndItem":False,
    "GatheringPart":False,
    "DefaultTraceCode":{},
    "PhantomManufacturingPart":False,
    "ConfigurableModule":{},
    "Name":partname + "_pyapitest",
    "Source":{},
    "AssemblyMode":{},
    "Uses@odata.bind":[],
    "DescribedBy@odata.bind":[],
    "References@odata.bind":[],
    "PartDocAssociations@odata.bind":[],
    "CATCODE":"520000",
    "Context@odata.bind":"Containers('OR:wt.inf.library.WTLibrary:110138')",
    "Folder@odata.bind":"Folders('OR:wt.folder.SubFolder:155247')",
}

The weird thing is that our IBA "CAT_CODE" can only be mapped when we remove the underscore and make it "CATCODE"...