SendNotifyMessage - Controlling another process?

I'm trying to automate Acrobat Pro 7 with the SendNotifyMessage win32 api command from my C# app. I created a .net windows service which watches a folder for a specific file. With the correct file the service launches the acrobat process via Process.Start() then uses SendNotifyMessage to simulate keypresses to get to the correct menu option.

The problem Im having is the SendNotifyMessage(hwnd_main,Win32.WM_COMMAND,0x19f3,0) infrequently works. At times the command is issued and the Enable Comment Save As dialog box appears as expected but other times its as if the command silently fails and nothing happens on the main window.

Is there something i can do to get more of a consistency when sending messages to another process? Better win32 api commands to check out?

I am using SendNotifyMessage because the resulting dialog box would normally not return control back to my app until it was closed down; this win32 function is async and so allows me continued control over the running process, and i also like the fact that i can specify a specific windows rather than relying on the current window with focus.

Thanks.

Have you checked if the acrobat software you are using supports OLE automation.

I bumped into these references, not sure if you it concerns you, but worth investigating.

http://www.adobeforums.com/cgi-bin/webx/.3bc330f9
http://p2p.wrox.com/topic.asp?TOPIC_ID=40612

It doesnt seem to support such capabilities for Enabling Commenting on a PDF from my Acrobat Pro 7.

I think the problem you will find with the SendMessage() / SendNotifyMessage() is that Acrobat may change its dialogs over time...and perhaps you wont be able to find the correct window anymore.