How to combine different values to one values in xpath mapping

Hi everyone

I think it s simple question but I m new on Adobe Livecycle Workbench

My problem is

I Have 4 different values such as

DocType                    int                  = 369

CustomerNumber        int                 = 123456

CreateDate       string or datetime     = 01/01/2010

DNZ*#                 freetext

BarcodeGathering     string

these are my values which come from the web service (except DNZ*# and BarcodeGathering)

All I want is

I want to gather all information such as DNZ*# CustomerNumber #DocType#CreateDate into BarcodeGatehering in xpath mapping

so I tried /process_data/@BarcodeGathering         "DNZ*#" + /process_data/CustomerNumber + /process_data/DocType + /process_data/@

but İt didn t work

can you tell me the right syntax

Also If you give other examples I really appericate that

thank you very much anyway