Invoice Draft

Hi All,

I have a query related to the invoice draft. I have declared a new variable under Studio->Invoices -> Fields and the name of variable is aaa_c and its type is currency. This variable is showing a * proceeded by the variable name in the fields section. I have also attached the screen shot.

Now, when I am defining this variable in Invoice draft then on printing the invoice it shows the variable name instead of the value input by the user. I want to print the value of the variable and also there is a grand_total predefined variable, so I also want to add the value of aaa_c in grand_total. Please let me know whats the best possible way to print the correct value and add the value in grand total.

Kindly help and also find attached the screen shots.