Good job ZEP, but here is another way that I use quite often on other types of awnings with the same or similar problem.
1. remove the outer 2 slats from the aluminum awning cover
2. separate these into 2 pieces by removing the outer retention screws and sliding them apart
3. repair the lead edge channel as per Zep's instructions
4. after inserting new poly cord (commonly known as pneumatic tubing) into the awning pocket, slide the repaired slat with the lead rail onto the awning.
*NOTE* if the original outer slat is too badly deformed and will be difficult to slide the fabric thru, you can usually switch these slats and use the rail from the second slat to run the fabric thru. This will allow you to slide the damaged one thru aluminum, which should be easier with no snags.
5. position the awning up near the remaining aluminum cover that is still attached to the trailer, and slide the remaining slat into both the upper (trailer) and lower (fabric with last slat) sections.
6. replace the end screws
7. remove the rear arm from the trailer and re-wind the spring per Zip-Dee instructions.
8. you are DONE!!!!