Hi Stefan,
I have below setup on my Windows 7 PC
D_Drive => d:\svn_sandboxes\project
This folder is mapped to T: with below command
subst t: d:\svn_sandboxes\project
I have checked out my project over T:\
Now I open by right click, "check-for-modification" dialog. From this dialog, I export the changes to another folder elsewhere. The exported contents have their 1st level folder names with 1st letter trimmed off.
I have further tested to export from "d:\svn_sandboxes\project". This gives correct folder names without truncation of 1st letter.
T: is required for my build system otherwise it does not compile. I also have eclipse project configured to T: for shorter path needs. I use eclipse only for software analysis and modifications.