Dyanamic Validation on fields based on Categorization

Hi Experts,

I have a requirment on selection categorization in Activity Type transaction ( BT125H_TASK ) we need to make some fields mandatory. like if we choose categorization C1 , Fields F1 and F2 are mandotory but in categorization C2 , Fields F2 and F3 are mandatory not F1.

So for time being we have developed logic in Badi CRM_SERVICE_OS_BADI and Order_save badi and I am using CRM_MESSAGE_COLLECT to display error message aand if error is there , i am raising Do_not_save in Order_Save.

So in my final output i will get Error Message based on this. But Our business needs the fields to be marked with '*' and red colored like we do it in mandatory field. so based on categorization those fields will become mandatory.

So as in above screen shot i have displayed error but fields i showed in box , I am not able to make them "*" and red colored How do i achive this , how to make fields mandatory programattically?  Help is appriciated!!

Thanks,

Dhruvin.