By the way, the use of p for pause (or comma for pause) is common feature of many phones, nothing to do with Tasker. You can append the code(s) to the end of your phone number stored in your contacts. For instance, you might create a contact called VoiceMail with a stored number of:
So, you call the "VoiceMail", and the phone will dial, pause, then dial 1234# for you.
Tom