It's not ideal, but it may be workable for you.
I have not been able to or find how to pin a new folder to the start menu (can be done with the taskbar).
I did get a folder to display with recent items (with sub-folders displayed).
What I did was to......
Change the Downloads folder name to 'what I want' from your Personal Folder or its Properties.
Then click on the Start Button, open properties -> click on start menu -> click on customize and then scroll down to Downloads click on Display as a menu.
The name change appears in the menu right hand side with folders displayed when you click on jump list. You may wish to change where you download to. I hope this is workable for your needs.