@p0wertje 

Thank you for this tips.
It helped me to spot the misplace of tier1_lr key in the vsvip part.

From now, I know how to set up a vs with all its elements (vsvip and pool).

So I have made a step beyond.

Next step, modifying this vs.

The short piece of available documentation says "Additionally, the same API (macro) can be used to modify any of the objects using PUT"

So I was hoping of a kind of declarative API but it seems not that simple.