Hi Sabine,
Due to an issue, the product list can only be used in Sales Order processing if also the Sales Quotes are active. This is expected to be fixed in 1608.
If you need to use the product lists in sales orders, please enable the sales quotes as well in Scoping/fine tuning but don't provide the sales quote WoC to any user/business role.
In 1608 you can then remove the scoping for quotes again. The removal of the quotes
scoping will only be possible if no quotes have been created. Therefore ensure that no user has the WoC Sales Quotes assigned.
Edit Project Scope -> Scoping -.> Expand Sales -> Expand New Business -> Enable Sales Quotes.
Regards,
Suman