What is the best way to do this? - HELP, ADVISE, IDEAS and CODE APPRECIATED!

Not sure if this is the best place for this but here goes.

I have an ASP.NET application (app A) that opens a modal popup window containing "App B" in an iframe (in a completely seperate domain).

We will pass to "App B" some data including:

1. a url of a non-visible page (on app A) that will be used to accept values coming back from App B and will write them to a DB
2. a url of a page were the user will be directed after App B is closed and the values are written to the DB

The user will do some things on App B and then they will click a button. In that button click, it needs to:

1. post some data back to App A that will be written to the db
2. close the modal popup that contains App B and then redirect the user to a predefined page

I do NOT control the architecture of APP B, only that there will be a button click event that posts some data back to APP A.

Management would PREFER that "APP B" be opened in an iframe within a modal popup but if it is not possible I can skip the modal window and just place it in an iframe but I'm open to other ideas as well.

Any suggestions, advise, code examples would be GREATLY appreciated. As usual, they want this done yesterday after waiting a year to tell me about it!

Please give me some ideas.

THANX!

Which part(s) do you have problem with?

I know JQuery libraries have the ability to show modal popups as iframes to ease the development of that, and well - the transmission of data could possible be sent as querystrings to and from the iframe page, which means it'll be a question of defining the information sent to and from the iframe.