How can i use alphanumeric qualifiers in items.xml and code generation?

Hi Folks!

I've created an Item-Type of an extended Product. For the attribute qualifier, i want to use alphanumeric qualifiers. For example:

attribute generate="true" qualifier="attr4" type="localized:java.lang.String" ...

Due to building, following error ocures on codegeneration: IllegalStateException: invalid attribute qualifier: ....attr?4(localized:java.lang.String):...::YAttributeDescriptor[myextension-items.xml:9(AttributeTagListener)][PROPERTY]!!

How can i solve this issue? Unfortunately,I have to use alphanumeric qualiferies.

Thanks! Cemal