Haven't done it on a Remora but I did on another skimmer. I drilled a hole in the collection cup inserted and siliconed a hose barb in place, attached a drain line to it and ran the line into a 1 gallon milk jug. Make sure you use a big enough tube as they tend to clog up with nasty stuff pretty quickly.
AquaC has those mods for remora. You can email them to get it from them. I believe they used fittings for 5/8" O.D. tubing. Go to www.proteinskimmer.com for details.