[news.eclipse.modeling.tmf] How to make a reference like model::someClas

[<xx.eckle@xxxxxxxx>]

I need to built a reference to an EClassifier of a specific model like this is done in the xtext-Grammar (~   model::classifer).
It works fine, but there has to be a whitespace between "model" and the "::"-separator, else i get a validation-error in the ui (mismatched input 'model::Package' expecting RULE_ID).

My Reference, the Model and its usage is defined as follows:

ModelElementRef :
	(model=[Model] '::')? classifier=[ecore::EClassifier];
Model :
	'model' package=[ecore::EPackage|STRING] ('as' alias=ID)?;
UseMyRef :
	'using' name=ID 'for' modelElement=ModelElementRef;


When using the alias ID of a defined 'model', there needs to be a whitespace in it like

model ::Package

How can i get rid of this? Where is the point i have to intervene?