You want to look at the Shaman base list. Shamans have spells for binding spirits into objects. Should be easy to extrapolate from there.
Also, if objects to contain demons were made as the focus of the summoning, and properly prepared (like, made with special materials, or cavered in proper runes, or bathed in the blood of a virgin hill billy elf, which are not easy to find past the age of 13...sorry, I digress), or some simular set up that a GM would be willing to approve, then part of the ritual would be casting master demon spell on the demon/object, which would then have to be made "constant" or the active master spell could be dispelled or dismissed/cancelled...perfect for a mage who doesnt want the users of the demon bound gear to survive, bwah hahahahahahaha.
lynn