BTS 2006 BTSService.odx Missing File

While Installing BizTalk Server 2006, I got one error message about one missing file; that file is :

G:\Msi\Program Files\Developer Tools\BizTalkProjectItems\BTSService.odx,

then I found out that this file is not existent in my CD, I pressed ignore, and resumed installation, however after few days I was developing one BizTalk Application, and I tried to add a new orchestration file, but every time I try to do it I find the left pane empty when I select Orchestrations from the left pane, this error aroused my anger, especially I searched on the Internet to resolve this problem, but it seems no one else got it but me, however I remembered that file I missed while installing BizTalk Server 2006, and fortunately I have another machine where I installed BTS 2006 before and I could add orchestration files, I got this file from the path above, and surprisingly the file size was ZERO !, I think that’s why I couldn’t find it on the ISO image I installed BTS from, I think the ISO creator I have used is not including zero files, I copied the file to the first machine, and luckily it has worked, but the question is that as long as this is a zero sized file, and it’s completely empty, why VS.NET 2005, recreates it upon startup when it’s missing from the BTS developer tools?