Bitlocker deployment

I am trying to automate a bitlocker image in Altiris, and have everything 99% good to go, but am stuck on the command to actually enable bitlocker.

I currenly have "manage-bde.exe -on C: -rp -TPMandPIN"

The problem is, it needs the PIN to be inputed twice, and I am not sure how to make the script wait, and put in the PIN when the computer asked for it.