PermissionsEx Ranking up with Signs?

I'm starting a Prison server and have everything set up except for ranking up. I need to be able to place a sign on a wall that will allow players to right click it and rank up for a fee. For example, on a server I know you place a sign like this:
[Promote]
RankName
$Cost
I would like to be able to do this with PermissionsEx and if not PermissionsEx I would like to know which plugin can let me do this. Also, this is my PEX permissions (not done yet but I will continuelike this):

Code:

groups:
  D:
    prefix: '&6[D]'
    default: true
    permissions:
    - modifyworld.*
    - essentials.spawn
    - essentials.balance
    - essentials.pay
    - essentials.signs.use.*
  C:
    prefix: '&2[C]'
    default: false
    permissions:
    - modifyworld.*
    - essentials.spawn
    - essentials.balance
    - essentials.pay
    - essentials.signs.use.*
users:
  Frenzy724:
    group:
    - C
  rg87654:
    group:
    - C