How to make a directory in an opened ftp port ?

Dear all: From the REBOL documentation, I know two ways to make a directory in a remote ftp server. One is make-dir and the other is open/new. However, the former requires one additional connection while the later has to check whether the directory already exists first. All I want to do is to upload a file to a remote ftp server and make a sub-directory beforehand if necessary without additional connections. The way to check if a sub-directory exists in an ftp port is mentioned in the REBOL doc but how to create a directory isn't. Any ideas? BR. Brain Lai