Remove the set screws to make sure the "masts" are not hanging up on them. It's a tight fit -- try twisting as you extract. Pliars with a soft grip (use a rag in the jaws if nothing else) should get it started. If that doesn't do it, shoot a little WD-40 in the vacant screw slot and where the rods meet the plastic. Last (if necessary), set it out in the sun and hope the differential expansion will help out.
If all else fails, let your dealer do it!
Tips: Mark the old rods with tape or a permanent pen. Once out, put a corresponding mark on the new rods so you should know when they are seated. A couple of light taps with a mallot or small block can help. Extend a centerline mark where the groove is so you can make sure it is facing into the screw once it's concealed. Don't overtighten the screws -- snug will do it.