iOS Add an entry to the "Open in" feature

Hi All,

I am a beginner in iPad applications.

I have an application developed for ipad. I want to invoke this application from email configured on ipad. i.e. when the user gets an email and there is an attachment. On long press on the attachment the Open in feature is available. When we select "Open in" feature we get list of options. I want to add my application to this list.

How can this be done. Please help

My application supports .pdf files. Now i wish to open the pdf files attached in the mail using my application.
For this i need to add an entry of my application in the Open in drop down box.
Can this be done ?