[Zope] Z Classes and Z SQL Methods

Hi, I want to create a Z Class that communicates with a database. I first created the Z Class, created an instance of it and put all my Connection and SQL Methods in the _instance_, figuring I put them in the Z Class when I got everything to work. I works now, but if I put everything in the Z Class, Zope complains that access to my SQL methods is no unauthorized. Recreating the method in the Z Class and copying the code doesn't help. Any ideas? Douwe