In fUML-1.3/1.4 - and Magic Model Analyst® (Cameo Simulation Toolkit®)) - CreateObjectAction is not allowed to instantiate a UML DataType or a SysMLValueType, only a Class as the < code>CreateObjectAction::classifier:
But there's an easy workaround in Magic Model Analyst® (Cameo Simulation Toolkit®). Just create an "empty" instance of the desired ValueType then drag it onto a ValueSpecificationAction. You can the populate it as desired using AddStructuralFeatureValueAction just as you would for any Class/Block object.