Hi Louis,
thank you for your answer.
Fortunately I don't need to create Request Area properties automatically, I have only to populate them from Service Catalog.
Maybe I found a solution, but I have to test it: to propagate a SC field to SDM Request Area property the field name in Catalog should be "ca_sdm_prop_0".
A useful link about this argument: sending properties by uss
Best regards,
Sutot