14D prepositions

I've been working a little on 14D and am thinking of adding adverbial prepositions. This is because the secondary predicates (or converbs?) require both pronominal prefixes and suffixes, making the form rather long. The attributive prefix could still be added for attributive usage and when the object of the preposition is pronominal, the preposition is incorporated by a dummy verb, turning it back into a converb or secondary predicate. This might even be used for host verbs with non-pronominal objects. Example:

kam tkusma "from the house" (adverbial)
ekam tkusma "from the house" (adnominal)
ikampu "from it" (converb?) i-kam-p-u HP-from-VERB-3S
kkampau "I came from it." k-kam-p-a-u 1S-from-VERB-PST-3S

The adnominal prepositions, such as GEN ha, probably won't be verbalized.