[Ecio78]

afaik the plain .zip doesn't support multi-part archives and that's what they needed due to the file size. by citing 7-zip (site) I was of course suggesting the .7z file format that is opensource and there are softwares and libraries freely available.

[kyrias]

http://www.ehow.com/how_6943340_extract-split-zip-files.html would suggest otherwise, though I can't try it myself at the moment.

  > … 7z file format that is opensource …

.ZIP is in the public domain ;)