WebDav and transfert retry, does it possible in upload?

Hi,

I have just setup a webdav server with the BITS option enabled.

Sometimes we have to upload big documents (100Mb to 1Gb)
in case of a network failure, what's appends exactly?
does the user can continue the upload?
does this works if there is a power failure on the user station?
There is anything special to do to continue the upload or its an automatic
process?

thanks.
Jerome.