I have four names: two middle-names (one was added in my childhood, when my grandfather died). No bank is prepared to acknowledge this - I'm only allowed a single middle-name.

Four names isn't really a lot; some German aristocrats (or their descendants) have 6 or 7 names, and it's quite customary for Arabs to list a shedload of their ancestors in their name (e.g. Ahmed bin this bin the-other bin whoever).

> the layer asked me to sign with the hyphen

s/layer/lawyer/

That's nuts. If a signature is anything, it's the way you customarily write your name. Fortunately my signature is unreadable, and nobody could tell whether I'd written a hyphen or not. I suggest acquiring worse handwriting (good handwriting is almost useless these days).