Hi Rene,
OK Ive tried a few variations as well, including those I know 100% work in XSJS, and I get the same error as you (objective style).
I suspect this is due to reference of spatial functions within procedure that are not recognised (within procedure). I know SAP are working on inclusion of spatial types with procedures, I really would advise you to post to Hana SPS07 and spatial data as the SAP chief architect for spatial has participated in that thread and thus more chance to see your query.