Our son will only take Soothie Paci too! I buy the cute plush (mini stuffed animal)pacifier clips at CARTER's (theres one at the Outlet in Allen and also one over by Stonebriar Mall, where Target/GattiTown is). You can bend the velcro end together and put it through the Soothie hole then velcro it (or just tie it off to make sure it stays!) Then we write our little guy's name in a Sharpie marker on the ribbon that attaches the plush clip to the Soothie!
I've also tried the hard plastic paci clip from Target that is made specifically for the Soothie-- but the paci NEVER stays in, falls off into the floor, etc. Sooo we just stock up on the cute plush clips!
As an alternative, you could purchase some of the Wubanubs-- the tiny stuffed animals that have the Soothie actually attached to them-- I've found them at The Sample House (also over by Stonebriar mall-- next to Carters actually!) or at USA Baby. You can "Google" Wubanub pacifier holder and it will come up w/their website and locations to purchase them.
Good Luck!
A.