represent the following description: xpfStringToEnumeration (modelId: GENERIC; aString: STRING) enumeration : GENERIC;
with explanation: To be completed 
... The xpfStringToEnumeration function converts the specified string to an aggregate
Actually xpfStringToEnumeration (1) does not convert to string to an aggregate, but returns enumeration element value and (2) expects not id of target model, but id of target enumeration, that could be received in call to xpfGetDefinedType, like the following:
enum_id := xpfGetDefinedType(XPXTARGETMODELID, enum_name);
enum_element := xpfStringToEnumeration(enum_id, enum_element_name);