Attachment on Website Portal Tasks

Hi, I have a need to manage duplicateable project with customers, and customers should submit attachments (PDF, zip, etc) to project tasks without entering desk.
This is a project tasks example:

  1. customer submit document A
  2. customer submit document B, etc
  3. studying documents
  4. create verdicts

Currently I am using:
ERPNext: v11.1.67 (version-11)
Frappe Framework: v11.1.61 (version-11)

I accomplish this by creating project template with tasks so I don’t have to tasks manually. I share project with website user (customers). However, when customer select projects, or custom web forms using projects doctype, customers presented with default/standard task list and standard task web form does not have attachment upload field.

When I use tasks doctype for web form I can upload file from portal, but it does not show any task created from desk, only customer generated task from website portal.

Is there any workaround to achieve my goal?