Just fitted ds2500 to our car c/w new grooved discs.
We had to fettle the edges of the pads to get them into the guides on our AP Racing calipers. A PITA.
We couldn't get the pad seating plates out (I think they are stainless), as corrosion had "grown" under these and pushed them out a little. Combined with the paint on the pads meant they would not go in.
So be warned, you might need to file your DS2500 pads a little to get them to sit in the calipers.
Only other option is to quite literally take the calipers apart. Good luck with that.