Hope you're having a great Christmas & New Year holiday :)
Unfortunately, I don't believe it is possible to control a Delay Line using Meta events :(
I'd do the following:
1. Create a Auto Fader and set its output to something you're not using. e.g. Control 31.
2. Cable the Fader to a Cable Switcher. (Set its Input to the output values of your Fader).
3. Create as many Delay Lines as required. One for each repeat and set the repeats individually for each. I created 4 in my test.
4. Cable from the Cable Switcher to each Delay Line. And make sure the Delay Lines are routed to the object/channel strip of your choice.
5. Set the range of the first fader to match the number of delay lines. e.g. with 4 delay lines I set the range to: 0 3.
This should work now. Not as elegant as being able to use meta events to control a single delay line... but a useful workaround I hope :)