I'm pretty sure the pinout is different between the Sleek and ZVM models. I looked into this about a year ago wanting to build myself a LOD for my Sleek. One of our sponsors, Qables, was trying to help me source a connector and then started selling one for the ZVM. But after doing some digging, I found out for some stupid reason, Creative changed the pinout between the two DAPs. I never found a source for a Sleek connector.
Now, this was a year ago so maybe you'll have better luck. I remember Creative never put out a lot of accessories for the Sleek and it was awfully difficult to get a dock for it (never seemed to be in stock). The more readily available accessories that involve a connector, the better your chances of sourcing a separate connector. Otherwise, I wouldn't be too optimistic.
Good luck!