Joomla adsmanager paypal modification

I am using the Adsmanager component with Paidsystem on a Joomla site. I need it setup so that a person can post an ad for free and then they can click "publish" to pay for the ad and have it published. In other words, the user posts the ad (flag in database set to 0), user pays for the ad (price according to what category it's in), then the ad is published (flag in database set to 1) when they come back from Paypal. This should be a fairly simple project. You will need to have some extensive experience in Joomla or Adsmanager to make this mod. I already have it setup so that the ad is automatically posted and unpublished. However, there is a small glitch where it's showing an unauthorized page in between and adding the image incorrectly. This will need to be corrected as well.