Warning message when creating material

Hi experts,

                  When creating material master and giving value in Purchase Value Key, it shows a warning message "check the value for purchase value key", our client wants to suppress this warning message, that is without a warning message they need to go to next tab.

                  Secondly under forecasting tab in forecast model field, they need to prepopulate an input 'J'. How I can do this in ABAP.

                   Please give your valuable suggestion.

Thanks