Well I don't believe this is exactly Arduino specific, so perhaps try posting this type of question in the motors section next time? I'm not trying to be mean/rude. You'd just get better support in the right area is all. I posted here by accident too. lol
But I don't quite know what issue it is you're having. Is it that the plug on the actuator doesn't fit into the shield?
Also have you seen these pages?
&
http://www.firgelli.com/pdf/L12_datasheet.pdf
You should be able to locate your pinouts from there and, if necessary, you may need to make a custom plug.