Appian Portals may not have access to internal files

I need to pass as parameter a document to a rule, however, it will only work in a interface. When in a portal url, it throws an error `at function a!httpformpartcheckvalue_appian_internal [line 37]: The function a!httpFormPartInputToFormPart is unavailable.`

rule!test(
token: local!token,
id: ri!id,
valorPrevisto: local!value_for_payment,
file: local!uploaded_file[1]
)

I've been debugging and I am sure that's because of uploaded_file. I would like to share my component to please get some insights from you

a!fileUploadField(
  label: "Please, upload a file:",
  labelPosition: "ABOVE",
  fileDescriptions: "excel",
  target: cons!CE_UPLOADING_FOLDER,
  maxSelections: 1,
  value: { local!uploaded_file },
  saveInto: {
    local!uploaded_file,
    if(
      a!isNullOrEmpty(local!uploaded_file),
      {
        a!save(local!currentFormStep, 1),
        a!save(local!variant_value_for_payment, 0)
      },
      null
    )

Just to remind, in a interface, that's 100% fine, but when that comes to a portal... I believe it doesn't have access to the folder of the `target` or something like. Hope you guys will help me one more time, so we'll both make contributions for the community. Thanks in advance