I need to open and edit pdf files from sharepoint ...

I have a SharePoint online (Office 365) doc library with pdf files.  The users need to be able to click on a document and have it open in Acrobat the same way a docx files opens in Word. They need to be able to check in and check out the document, make edits, save it back to the server, and then close the file, the same way it works with Word.  I've done extensive research into this only to find out I need to edit the DOCICON.xml file on the SP server.  Since I'm on SharePoint online, I'm not able to do that.   Also, I've read that an Internet Explorer Add On called "Adobe Acrobat SharePoint OpenDocuments Component" is needed to make this work.  I don't have that add on, and I can't figure out how to add it. any help would be greatly appreciated.    I'm using acrobat XI Pro, SharePoint Online 2013, and IE 11   thanks, ... View more