How can I keep the original file [commit] timestamp on Subversion?
You can set it in .subversion/config:
[miscellany]
use-commit-times = yes
Although you will have strange side effects if we are talking about source files.
For example, you build your software and do svn update. Now the timestamp of the updated files is older than the timestamp of the build result file, and it won't be rebuilt even though some source files changed. Be very careful with this setting.
If you are using TortoiseSVN, there is an option. TortoiseSVN -> Settings -> General -> "Set file dates to the 'last commit time'".
