Description of HEALPix in STC

[Thomas Boch]

I'm forwarding to the dal and apps lists a message I initially posted on 
the DM list :

Hi,

I'd like to describe in STC the coverage of a catalogue as a union of a 
set of HEALPix pixels, possibly mixing different levels of pixelisation. 
I am in particular looking for examples of a serialization (STC-X or 
STC-S) of such a description.
As I could not find such an example in the STC document, I'm seeking for 
your help.

Cheers,

Thomas