I'd rather not have this special case since we have nothing in place to handle it. In French there's also tu/vous (informal/formal) and we use "vous" as that's generally what's used in software. Isn't it similar in German? If it should have been "Sie", maybe change it all to this then? Looks like in Spanish they also use the formal "usted" and same in Chinese with the formal "您".
Regarding the ampersand, it's up to you where you put it. Normally it's on the first character but if that letter is already taken, it goes on the second one (or some other letter). This is the letter that gets underlined when you press "Alt" on Windows. Then you do Alt+F for example to open the "File" menu.