While clitics cannot appear in inflectional affix templates, they can
delineate the set of categories they attach to. Under Grammatical Info.
Details, you will find the "Attaches to Categories" field (you will
probably have to check "Show Hidden Fields" in order to see it). Set
the categories there. You can also see the "Attaches to Categories
field" entry in the user helps as well as section 2.3 Clitics in the
conceptual intro to parsing document.
--Andy