Doubt s in ABAP HR -Enhancements

Hi All,

i am doing enhancement for infotype 2,

but the problem is ,

whenevr we enter the data of infotype 2 in 'PB10' it should check the date of birth with system date ,if the deff is below 18 ,then i have to pass message lik e'he is below 18 years' like that i have to pass ,

but the main problem is ,

""""i am able to getting that message in the infotype 2 screen ""

but i would like to pass that message in first screen itself ,

like in PB10 itself,

how can i procede,

plz let me know,

this is very urgent.

thanks,

sai.