Please note, if you want to make a deal with this user, that it is blocked.
It depends on your target.
dde is not bad, but ole is based is more silent.
I used DDE before everybody start speaking of it.
It works better if you provide 2 documents like : 1 not infected and the other have some problems but works if they click.
you can (always works) you tell them "theres two docs, but one is made with old office and it crash sometimes.." and you specify them that they office program will ask them for reparing the file..
you don't insist too much on it, just tell it, don't show too much emotions..
their are tons of things to say for praparing them to accept when the popup comes

)..