yes both ftpii and wiixplorer can transfer files over network
BUT both dont support the wbfs filesystem
only fat and maybe ntfs
afaik the only way to transfer to wbfs is using linux and ndb
but as all homebrew wifi its kinda slow
i sugest try wiixplorers ftp/smb to some fat drive to test the speed
and if you like it convert to using fat instead of wbfs