[Zope] creating product instances using dtml

Howdy All, I've been trying to figure out how to make instances of a product without using the management interface. For example, lets say my product is called MyProduct and I've defined manage_addMyProduct in the .py file. I can create the object by spoofing urls, but I'd like to be able to create the object using dtml. I've tried: <dtml-call expr="someFolder.manage_addMyProduct('someId')"> but the manage_addMyProduct method can't be found. Does anyone know how this is done? Thanks, Micah