I have tried with same you said. Again i am getting same error.
<a:KeyValuePairOfstringanyType>
<b:key>customerid</b:key>
<b:value i:type="c:string">1900ec4b-1234-4f72-9190-8ffbb551f42a</b:value>
</a:KeyValuePairOfstringanyType>
Sample code:
<s:Body>
<Execute
xmlns="schemas.microsoft.com/.../Services"
xmlns:i="www.w3.org/.../XMLSchema-instance">
<request i:type="a:CreateRequest"
xmlns:a="schemas.microsoft.com/.../Contracts">
<a:Parameters
xmlns:b="schemas.datacontract.org/.../System.Collections.Generic">
<a:KeyValuePairOfstringanyType>
<b:key>Target</b:key>
<b:value i:type="a:Entity">
<a:Attributes>
<a:KeyValuePairOfstringanyType>
<b:key>uor_firstname</b:key>
<b:value i:type="c:string">mahes</b:value>
</a:KeyValuePairOfstringanyType>
<a:KeyValuePairOfstringanyType>
<b:key>uor_lastname</b:key>
<b:value i:type="c:string">tdev</b:value>
</a:KeyValuePairOfstringanyType>
<a:KeyValuePairOfstringanyType>
<b:key>uor_email</b:key>
<b:value i:type="c:string">mahes@dev1.com</b:value>
</a:KeyValuePairOfstringanyType>
<a:KeyValuePairOfstringanyType>
<b:key>uor_preferredintake</b:key>
<b:value i:type="a:OptionSetValue">
<a:Value>183240000</a:Value>
</b:value>
</a:KeyValuePairOfstringanyType>
<a:KeyValuePairOfstringanyType>
<b:key>description</b:key>
<b:value i:type="c:string">tews
tet
tete.</b:value>
</a:KeyValuePairOfstringanyType>
<a:KeyValuePairOfstringanyType>
<b:key>uor_levelofstudies</b:key>
<b:value i:type="a:OptionSetValue">
<a:Value>183240000
</a:Value>
</b:value>
</a:KeyValuePairOfstringanyType>
</a:Attributes>
<a:EntityState i:nil="true" />
<a:FormattedValues />
<a:KeyValuePairOfstringanyType>
<b:key>customerid</b:key>
<b:value i:type="c:string">1900ec4b-1234-4f72-9190-8ffbb551f42a</b:value>
</a:KeyValuePairOfstringanyType>
<a:LogicalName>incident</a:LogicalName>
<a:RelatedEntities />
</b:value>
</a:KeyValuePairOfstringanyType>
</a:Parameters>
<a:RequestId i:nil="true" />
<a:RequestName>Create</a:RequestName>
</request>
</Execute>
</s:Body>