Dave,
That alone won't work. I just set up TVH and had the exact same problem. Apparently the pre-defined muxes only contain one single (or one valid) transponder (TID=1003 on Astra 19.2E) that is used for initial scanning. And that transponder doesn't provide proper NIT data (many transponders do not). So only 6 services are found.
Mario,
If you add one mux manually that carries proper NIT data, you can find all services (I just scanned and found 119 muxes and 1603 services). Like Dave said, you should set "Network discovery" to "New muxes + changed muxes". See attached image for further details on the manual mux (TID=1019, "ARD Digital").
-- judges