I did mine a year ago,
1. Remove rust until see the hole
2. Remove all damn glue.
3. Apply "Hammerite Kurust" on rusty area, wait until it dry then apply again.
4. Send my car to weld the hole area, apply some Kurust on weld area.
5. Paint Kurust area with 'Hammerite Direct To Rust Metal Paint'
Both of this items and be found at ACE Hardware.
Too bad I live in Penang, I got this from EBAY.
Result until now no problem,. :)
normally u will see rust few months later if u let painter shop to repair rust.