CSS Navbar - Can't edit the buttons text

Hello Guys,

So I'm having some trouble editing my Navbar on phpBB2.

Aim :
Use CSS to generate my navbar buttons. It's easier to create/edit, and only uses a 1px wide bg picture, so fast to load and takes little space to host.

Solution :
I create a CSS sytle for the navbar and, in the admin panel under "Headers & Navigation" I set the option "Display only images in the navbar :" to no. Works fine but

Problem :
Some links texts aren't appropriate for a menu. For exemple the private message button will show "You have no new message" instead of the usual "PM" caption. Same problem for the login/logout button. Under "Headers & Navigation" in the buttons propriety the option to edit the link text is grayed.

Workaround :
Using the custom overall_header_new, I delete <td align="{MENU_POSITION}"{MENU_NOWRAP}>{GENERATED_NAV_BAR}</td> and create a custom Navbar using <a href="{U_PROFILE}" title="{L_PROFILE}" accesskey="u">{L_PROFILE}</a>. By doing this I can replace the 2nd variable {L_PROFILE} by the text of my choice. This would fix my pm/login buttons issue.

Workaround problem :
I can't find the {U_XXX} variable for each buttons. So Can someone provide me a list of the {U_XXX} variables for each buttons, or even better provide me the code of a complete {GENERATED_NAV_BAR}which includes all the javascript IF arguments for the pm/login/search buttons.
With this I will have all the tools to make my CSS navbar work.

I hope my request is understandable. Thx in advance for any help.