preserve the as-is date

[hbvis]

I'd like to preserve the as-is date/timestamp (mtime) of the files when I transfer them over the webdav and/or web interface, rather than have redmine_dmsf create them with the current date/time.

We want to migrate our document file storage system to redmine_dmsf and therefore we have a number of forms and documents that haven't changed since some years ago. We like to retain their time/date instead of showing that they were all created on the upload date.

It would be nice if the web interface also had a checkbox to "preserve time/date".

How can I achieve to preserve the mtime of the files?