It would be great if there was one single place to setup user preferences, but to my knowledge there does not exist one. Therefore you have two options.
a) Expand the APM with a user_preferences table: "package_id,parameter_id,party_id,value" and store the values there
b) Do it on your own in the reminder package.
I do not thing that the new ams service could be used for this, but maybe the ASM people have more of an insight there.
