Attaching Files to Cards is Icky+example

I have a 'Client' card type. In each Client we should have an '+Attachments' section - a list of files that belong to the client file (scanned docs, pdfs, etc.). The end user should be able to upload files easily in a way that will display in a list, in the Client's card. Also, deleting the Client card should cause all attached files to be deleted as well.

I can see only one way to set this up: the 'Client+Attachments' is a card of type 'Pointer'. To add a new file to the list, the user edits the pointer, adding another card to the list. When the user adds a new card to the pointer list, this new card is added as a 'Basic' card by default, and the user then must select 'File' as the correct card type - there does not seem to be a way to let the pointer know that we want to add 'Files' by default. That in itself is annoying to the user, but the not the main problem: the user must remember that the name of the new File card must start with a '+' - otherwise it won't be 'connected' to the 'Client+Attachments' hierarchy... Users inevitably forget to add the '+', and then you have file cards, with files, uploaded all over the system, unrelated to any client.

Is there an 'elegant' way to accomplish this?