Interesting. I also bought the PC CE digital download for this purpose, and also got an email from Digital River this morning, but mine looked like this:

Digital Rights: The_CD_key_that_comes_as_part_of_this_purchase_has_been_integrated_with_DLC_items_Please_note_that_the_DLC_items_no_longer_require_an_additional_code_to_access_your_content_

Mogstation doesn't show that I have CE now either. Hopefully this will sort itself out as we go along. I'm sure they are more focused on getting the servers stable with as many people as possible on them than getting CE items to people at the moment.