How do I add my disability verification letter to my Turbo Tax electronic filing?

I took an early withdrawal from my IRA and I am exempt from early withdrawal penalties due to permanent and total disability. Turbo Tax has automatically included my form 5329 to accompany my filing with the correct indication of disability. Most information I can find says I need to also include proof of my disability with my tax return filing. I have the proof but don't know how to add it to my Turbo Tax e-file. How do I add my proof of permanent and total disability to my Turbo Tax e-file to accompany my form 5329 to avoid early withdrawal penalties on my IRA withdrawal?