In MS CRM 4.0 SQL database there is a table containing settings for all entities present in the system and it is called… Entity. In this table there is a column named IsCustomizable and this is set to 0 (zero) for the PriceList entity.
1 Open SQL Server Management Studio
2 Connect to MSCRM database (not the config one, but the real one with MSCRM tables)
3 Run following update command:
UPDATE ENTITY
SET ISCUSTOMIZABLE = 1
WHERE NAME = 'NonCustomizedEntityname'