Creating marketing list with SOAP - Error with optionset

Hi all,

I have some problems creating marketing list with PHP, using SDK. I have a problem with the field createdfromcode, when I use picklist/optionset type I get the follow error:

picklist'. The deserializer has no knowledge of any type that maps to this name. 

Code:

<b:KeyValuePairOfstringanyType>
  <c:key>listname</c:key>
  <c:value i:type="d:string" xmlns:d="www.w3.org/.../XMLSchema">Lista test 0</c:value>
</b:KeyValuePairOfstringanyType>
<b:KeyValuePairOfstringanyType>
  <c:key>createdfromcode</c:key>
  <c:value i:type="d:picklist" xmlns:d="www.w3.org/.../XMLSchema">1</c:value>
</b:KeyValuePairOfstringanyType>

Does anyone know which fact is the right one or if the error comes from another part that I am not taking into account?