SendKeys and UploadFile keywords are not responding with disabled fields

I use UploadFile or SendKeys keywords and upload files. However, I ran into this form where input field is disabled (screenshot below). On the form, user will click on “Add Attachment” button and the modal opens up. Once user selects the file, file name shows up in the disabled input field.

It seems like UploadFile and SendKeys keywords are not working in this case. Can you help navigate this situation?

Thanks in advance for all the help!