Add two textfields as atribute. Prestashop 1.5.x

Description: I would like to add two text fields as customization atributes for some of the products of my store. User only could activate the fields clicking in a droptext option or checkbox* to activate both fields. (So also price increases when activated checkbox or chossen droptext option.) *Like this example: [login to view URL] Specifications: *Must be compatible with PS 1.5.x (multishop compatible) *The first text field is for names (from 0 up to 15 char), the second one for numbers 0,1 or 2 char. Extra: (Will be considered to pay extra or to chose the proper developer) 1.- Is prefered Droptext than checkbox 2.- if added funcionality of checking if at least one of the fields has been filled up (Only when the checkbox/dropmenu is activated ).