Discovering database sizes


I've been reading through documentation and posts regarding a customer requirement.
They would like to know the individual database sizes, on MSSQL. I have the discovery running fine with an AD user, it does get plenty information out of the SQL server - but I can't seem to find any size information getting pulled at all.
Does UCMDB even provide this detail, or am I missing a permission(this should be in master/sysdb tables) somwhere?