Getting started with SData (posting/creating customers)

SUGGESTED

So I've got SData installed and working. I can ping AR_Customer to get a list of customers. However, attempting to post to this endpoint with the following body fails:

Of note, I've slimmed down the payload to only what is known to be the simplest required fields.

<?xml version="1.0" ?>
<entry
    xmlns:atom="">www.w3.org/.../Atom""
    xmlns:sdata="">schemas.sage.com/.../1""
    xmlns:opensearch="">a9.com/.../""
    xmlns:sync="">schemas.sage.com/.../1""
    xmlns:http="">schemas.sage.com/.../1">">
    <id/>
    <title/>
    <content/>
    <sdata:payload>
            <ARDivisionNo>00</ARDivisionNo>
            <CustomerNo>KCUSTOM</CustomerNo>
            <CustomerName>This is a freshly created customer</CustomerName>
            <SalespersonDivisionNo>00</SalespersonDivisionNo>
            <SalespersonNo>SLE1</SalespersonNo>
        </AR_Customer>
    </sdata:payload>
</entry>

Response:

<?xml version="1.0" encoding="utf-8"?>
    <sdata:diagnosis>
        <sdata:severity>error</sdata:severity>
        <sdata:sdataCode>ApplicationDiagnosis</sdata:sdataCode>
        <sdata:applicationCode xsi:nil="true" />
        <sdata:message>Exception caught during the processing of a message
Verb: POST
        <sdata:stackTrace>System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at System.ThrowHelper.ThrowArgumentOutOfRangeException()
   at System.Collections.Generic.List`1.get_Item(Int32 index)
   at Sage.Utilities.Collections.MarshalByRefList`1.get_Item(Int32 index)
   at Sage.MAS.SData.SqlRequestHandler`1.GetEntryFromStream(FeedSerializer feedSerializer, Stream stream)
   at Sage.MAS.SData.MAS90Adapter.PvxAdapter.ExecuteOperation(OperationType eOperType, IRequest request, RequestContext requestContext, IRequestHandler requestHandler, FeedEntry&amp; aFeedEntry)
   at Sage.MAS.SData.MAS90Adapter.CMAS90Adapter.HandlePostRequest(IRequest request, RequestContext requestContext, IRequestHandler requestHandler)
   at Sage.FR.SData.Adapter.HandleRequest(IRequest request)</sdata:stackTrace>
        <sdata:payloadPath />
    </sdata:diagnosis>
</sdata:diagnoses>

Any ideas on how to go about creating customers via SData? Or, if not possible, where I can get some good documentation regarding working with SData or BOI?