I have looked into it. The reason "H" gets you "Niet Instappen" on the DRIMs, is line T3. Tramline T3 shares tracks with line M5 between Denia and Westwoud, and at Westwoud, there are two platforms along each track; a high platform and a low platform.
When on route to Garenmarkt, line T3 uses the destination letter "H". When you are at Westwoud, the R-Net DRIM (for the tram, on the low platform) will then show "Garenmarkt", while at the same time the RET DRIM on the hogh platform should show "Niet Instappen" (as there is a low-floor vehicle next to the high platform).
Therefore, I can not make "H" show "Cirkellijn Centrum" based on "H" (in explore mode), or else that would also show up at Westwoud.
If you want to make an activity using Cirkellijn Centrum, I suggest you use the CTD file attached to this post. It solves the problem at GGH-NOP, and has the correct destination (ID 92) set at the two routes. U can now use "H" to drive the route, and when using it in an activity, it will show "Cirkellijn Centrum". But in explore mode, it will keep showing "Niet Instappen".
EDIT: Cirkellijn Centrum routes did not include stop at Guggenheim Museum yet. This has now been added.