So here is what happened. On a 64 bit Windows 2008 server, I got the required BizTalk & Visual Studio components installed and configured along with ESB pre-requisites. Once done with the ESB Toolkit configuration, I started with creating a sample itinerary.
Created a new C# Class Library project and right clicked the project to "Add">"New Itinerary…". However, when the template selection dialog box came up, the itinerary template was not visible. Tried a couple of things including restarting VS in admin mode (common remedy), repair the toolkit installation, repaired the Visual Studio 2008 DSL SDK etc. However, none seemed to help much.
Apparently, the item templates were not properly registered with visual studio. So the fix was as simple as running the below command –
After this, I restarted the Visual Studio and was able to get the itinerary template thereafter.