Hi, yes, we are hoping to trial for our BH in the Spring. I agree, there should be a LOT more emphasis on keeping the Boxer a working breed. SchH and similar sports are a great way to keep the Boxer's heritage. I suggest you google "USA-Box", it is a GREAT organization dedicated to the working Boxer. I am a member there, and it is a worldwide club. It is over-seen by the FCI which IMO, is a MUCH better organization. The USA-Box team has many members who compete their Boxers in agility, frisbee, obedience, SchH/DVG, IPO, Ring, etc.
Last November a member named Frank Ceci and his SchHIII Boxer Max competed in the DVG nationals and did very well. He and also a lady named Minna competed w/their Boxers in the ATIBOX 2007 in Italy.
Good luck with your Boxer and don't be discouraged if it's not going so smoothly. Boxers need to be trained differently than GSDs. The USA-Box info can help you w/that. Also, if your Boxer is not from a working pedigree, she may not have the drive or nerves needed for protection sports. That is OK too! The important thing is you both have fun, and as far as tracking and obedience, your dog should do just fine!