"Uploading" Attachments to Sell

Hi,

we would like to have a "simple" workflow and can not build this with zendesk sell. The workflow is:

1. We get customer information from out website and trigger a cloud function.

2. From cloud function: create a customer and deal in zendesk sell and attach a product to the deal

3. From cloud function: generate an offer (PDF) and attach to zendesk sell. 

This does not seam to be a complex workfow. BUT we just discovered, that this ist not possible via any Zendesk API, as we can not upload attachments via API to a deal. Uh....

One can upload manually, but due to security it seams not possible to "mock" the manual upload somehow. This really is a great downside, so I investigated other options.

I came across Google Drive and Dropbox integrations. These work manually and for sure we can upload documents there via API. BUT: One does not know the folderid the Zendsek Google Drive" plugins creates for a deal AND it doesn't create a folder on Google Drive/Dropbox, when the deal is created. So there is no way to create a Google Drive folder automatically, when we create a customer and deal. This breaks our automation flow, as now we can not create a customer and attach a document to a new deal automatically again.

Do we really have to write our own zendesk App ONLY to upload a document automatically to a deal? 

We are still evaluation Zendesk and I think this may be a dealbreaker for us. Does anybody here have the same issue?

Mario