iPad app & Mac app, how to do promotion with applications on different platform?

[peterphonic]

I already post a question regarding if it was possible to make iPad app free for users buying a Mac app, via apple store. I got an answer that it might be possible via promo code, in the following scenario

1. The user buy the iPad app
2. A promotion code is generated for him,
3. User goes to buy the Mac app, he enters the promo code so he get a discount for the Mac app

Question 1 :

• 
  Does this scenario is possible?

Question 2 :

• If yes, the promotion code generated when user buys the iPad app, is it a unique promotion code? Or he will be able to give the promotion code to his friends, and these friends will get the discount on the Mac app too?

Finally, the following scenario is the preferred scenario:

1. The users buy the Mac app via app store
2. A promotion code is generated for him
3. Users goes on iPad app store, to get the iPad application. He enters the promo code, and he gets the iPad application for free
4. (Users not buying the Mac application have to pay for the iPad application)

Question 3:

• Does this preferred scenario is possible?

Question 4:

• Same as question number 2

Question 5:

• Anybody have a better idea how to do promotion like this? (Buy Mac app and get iPad app for free etc...)

Thank you very much!