Pic 16f628a keypad Firmware Redesign

Hello , this is a upgrade of an already existing project : We have a pic16f628 in a very simple pcb board this pic is able to to read a 4x4 keypad from a third part device ( like a interception of keys) . the device send keys to his own circuit and this pcb is able to identify the commands sended and execute commands based on this. actualy this pic is designed to read as 4x4 keypad format and retrieve the keys using a ps2 output We need to change the keypad mapping from 4x4 to 3x5 and also we need to add a tx output , so the pic will have 2 outputs one for ps2 and one for tx output. We already have a functional in production pic working for more then 4 years now we need to make some upgrades. more details will be discuss whit selected freelancers If you dont have time to read the description , please dont waste your time posting on my thread because i will not answer. Si hablas español , ya estas un paso al frente de los demas. mayores informaciones van a ser dadas en privado si estas en chile facilitaria demasiado el desarollo .