Changing Image Upload Tab

I have a custom CMS that I developed and I need to perform several additional checks and provide the user with options to place the file on the server before they can even browse their computer for an image file to upload.

I have already created a handler for this on my side, however I need to replace the tab on the image dialog so that my custom upload handler is shown and not the browse and send to server buttons.

I checked the documentation and there is the "FCKConfig.ImageUploadURL" setting however that just changes where the upload form submits to.

Is there an easy way to change this (I doubt it) and if I simply include an iFrame for that tab what javascript should I use to set the image into the editor when the upload process is complete?

Thanks,