No problem, always happy to throw in my 2 cents.
For court your girlfriend is going to have to establish that the signage for that spot was improper so if she hasn't already I would go and take some pictures to show that there was no vertical sign there.
When your girlfriend gets her court date in the mail she should file for disclosure and get a copy the ticketing officer's notes. See if the notes mention anything about the signage, if the notes indicate that there is no vertical sign then that will help her case.
When she gets to court she should plead not guilty. After she enters her plea the prosecution will call their first, and only, witness which will be the ticketing officer. After the prosecutor has asked all their questions she will be given a chance to cross examine the officer. She should ask the officer about the signage and see if she can get them to admit that there was no vertical sign. If the officer admits that there was no vertical sign she can then show the Justice of the Peace a copy of regulation 581 and ask that the case be dismissed.
If she can't get the officer to admit that there was no vertical sign then your girl friend will have to take the stand and testify that the sign wasn't there. At this point she can also ask to have the photos admitted into evidence. There are some rules around how to admit photos into evidence that I'm not totally familiar with so you will probably want to look those up to make sure you can get your photos admitted into evidence. Be aware too that if your girlfriend takes the stand the prosecutor will be able to cross examine her so she should be prepared to answer the prosecutor's questions.
If you've got some extra time it might be worth doing a check for case law to see if this issue has come up in court before. If it has there might be some case law out there that will help your case. http://www.canlii.org/en/ is a great resource.
Also worth noting is that when your girlfriend checks in with the prosecutor on the day of her trial she may be offered a plea bargain. Since this ticket is only a fine and will not affect her insurance a deal might be worth considering. If they reduce the fine enough it might be worth it to take the deal and run, but she won't be able to decide that until she sees what the prosecution is offering.
Anyway if I were fighting this case that is how I would proceed, although I'm not a paralegal just layman who has done his own research to fight his own tickets, so some one with formal legal training might have a different approach. Good luck and keep the forum updated on how the case goes, it is always nice to be able to see how things turn out.