Yup, just checked the procedure for removing the rear calipers. It essentially says to grab the cable end with some pliers, pull on the cable a bit and slide it around the "rear parking brake lever" (what the manual calls it - the clip thing that holds the cable end). No mention whatsoever about releasing tension on the ebrake handle. When I did mine, it was realllly tight (new cables). So I would say double check to make sure your ebrakes are released (lever is all the way down) and just give that suma***** cable end a good pull. You should be able to pull just enough slack to slide it out of the lever clip thing.
Edit: I don't know if you have a manual or not, but if you do and wanted to see what I am referencing, it's section 06-04-3, Caliper Removal (this is a 95 manual).