Wilsonjc,
I don't work in Europe, so we don't get to use the Hidden and Absorb fields for dialed digits, but the problem is rather simple to me.
Create your Dialed Digits, by the way you don't need the 1571 rule.
Create a new Facility Group and just put in Dial Rules 9 and 10, nothing else.
Create a new Route that has the 1571 as the pattern, this is how it determines what is being called.
Then add your new Facility Group to the new Route Group. Set the new Route Group us as high in the order as you can so it will match with the 1571 before any other Routes do and then Test.
So basically what we are telling the system to do is this.
1. Look in Route Groups for a Matching Pattern: 1571
2. Look at Facility Group for Trunks and what to Dial.
3. Pick up a Trunk from the Facility Group and send out the Dialed Digits.
Since we are not echoing anything from the original dialed pattern the 1571 doesn't enter into the equation and it should dial the added digits that you provided.
I think since you are adding your dial rule 8 it is dialing the 1571 even though you have the Absorbed checked. When I look at the help file it doesn't explain that feature well, but I think it is still dialing your 1571 since your original rule is to Add.
Hopefully that will work for you.