Word Document Opening from c# after mail merging and then editing

Question

Hi all,
 Thanks a lot for your help in advance.
I am doing a Mail Merging Application. I can get all data from the source (database, file or anything) and using mail Merge fields in Word Document from C# code, I open up the word which is merged with data from database.
 
MS Word Document Opens –
  
 --- should this be open in IE
 --- Or should this be open as ordinary MS Word on Desktop
 
  The problem is if I open it anyway, I loose all control over the Word Document which is opened. I don't want to do that. I want to keep control over it and allow the Users to update the document with some standard messages which we have in the project. What that means is, the messages will be selected and those messages selected will be put at some point where cursor is kept in the document.
 
So, when mail merging happens
 
MS Word Document is opened.
A pop up with standard messages is opened.
User selects the messages he/ she wants to insert into the MS Word Document which is opened.
 
For these things to happen, I should have control over the MS Word Document which is opened on the client side. Do selection of the messages and populate in Word document (this is my understanding, is there any way to do it easily).
 
The Issues are:
 
I need a way to open the MS Word Document in a controlled manner where I can still control the User editing or help user in editing when he / she clicks on my standard messages and wants them to populate on the MS Word Document.
How can I save the MS Word document and make sure that user is not saving it locally and has to upload it again to save it on server.
 
 
I Hope I am clear in explaining the situation, please find the attachments which show the MS Word Doc and the popup on side .