Normally you don't need to define your name with an xpath like that.
Have a look at http://world.episerver.com/blogs/Linus-Ekstrom/Dates/2013/12/New-standardized-format-for-content-type-localizations/ and it might help you.
Yes, that's what I normally do. But I also wanted to check if I can define a name with an XPath and noticed that it doesn't work in On-Page Editing view.
I've decorated a page property with a Display attribute like this:
And created an XML under Resources / LanguageFiles:
When I'm editing the page in All Properties view, I get My Property, as expected:
But when I edit the page in On-Page Editing view, I get /propertynames/myproperty:
Tested with Alloy.