I have a project with it depends on another project Core, i use svn:external to maintain the dependency. when i go to create an update of my project, i export those changed files of two tags of my project, but the changed files in Core won't be exported.

For example, my project 2.0 depends on Core 1.0, where 3.0 depends on Core 2.0, then i create an update, changed files of my project 3.0 will all be exported, but none of those in Core 2.0

This can be done thru a two-steps process, first export changed files of the project 3.0, then the Core 2.0, it is ok if i can remember it everytime when i create an update, but in case i forget someday, the broken update will most probably cause a crash. I wonder, is there a way to cover this situation in TortoiseSVN, will let me do it in one operation?

I use TortoiseSVN + VisualSVN