IDOC - Field conversion

Hi All,

I have created IDOC conversion rules for customer master data under segment E1KNA1M in BD79.

One of the conversion rule is to add a "P" in front of the customer numbers in the target client. For example - source client: cust num = 1234567, target client: cust num = P1234567

How do I add this conversion rule? Which rule type should I use?

Appreciate any help!

Thanks,

Charlene