The Resume feature, which uses the REST (restart) command if you were to do it on a command line client side, is supported in IIS7 and newer. There's nothing you have to do. It really depends on the FTP client you are using whether it supports it or not.
I recommend Meinolf's suggestions to check the IIS forum.
I also recommend changing this thread type from a DISCUSSION to a QUESTION, since after all, you're asking a question.
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