Personally, if it were me, I would pack this 'stuff' up in black trash bags and then txt hime the following message:
"your things are packed up, and will be placed outside my door at 8:00am on tuesday 4/17/12. IF they are not picked up by 6:00pm they will be thrown in the dumpster."
Then I would go on about my business and do as I said. If I lived in my own home, his things would sit by the front door until 6 pm and then I would throw them in my garbage can for trash pickup.
The same if I lived in an apartment or a townhouse.
Since he is your EX you really do not need to talk with him or answer his txt messages.
J M H O
Love and hugs,