Integrate Desk with other Zoho Products

Integrate Desk with other Zoho Products

I already have Zoho invoice and Zoho Assist.

I am trying a free trial of Zoho Desk but none of my customers show up, my company logo, nothing transfers over.  Is there no way to get the data located in Zoho invoice over to Desk?

Also, I would like my customers to be able to log into their Zoho Invoice Portal and create tickets for Zoho Desk.   Is this possible?