Good luck to you.......
I did once and found the info in the HPL quite specific.
It depends on having the administrator on your side - which he really should be!
Our administrator refused to cooperate so we had to do all the work ourselves without the official address list (the call should go out on paper/post and not only by email).
You need 25% of the community to support the meeting - a petition etc is fine. We attached the petition to the official meeting call.
I am told that I am one of the very few non-Spanish people to call an EGM by petition - but you do need someone with community legal knowledge on your side. The process was both interesting and somewhat high tension but well worth it.
Although we obtained a good majority on the single item of removing the president we declared the decision a draw and so the president was given a clear indication of the mood of the community. He was defeated at the next AGM.
My real message is not to be put off by the doubters and lack of official support. It is your right as a group of owners to question matters within the community and that should be the first rule you clarify and enforce.