Custom Stage

[Bilwakunj]

Hi,
In our project, we are using couple of "custom stages". when we did the import/export from the development to testing environment we found out that everything was getting compiled except this. We tried the import/export using .dsx as well as xml format , but the problem was persistent so finally before compiling we registered stages using the "Generate" from the Datastage Manager which created the corresponding entries into the new environment and we were able to compile the stages. I'm curious to know why this could happen? Why it's not working without "Generate"?