The reason I would like to use SQL Express instead of the embedded database is that I need SQL for other services on the same server, and I would prefer not to mix to many database engines on the same machine (it will run Firebird and SQL Express).
I understand that it's not officially supported but are there any known problems or tests made that indicates it shouldn't work. The express versions are afaik not different to the full versions except the restrictions (4GB Database, 1GB Memory, 1 CPU).