Nevermind, I went ahead and did it.
Created the tar using the cygwin and tar with ustar parameters.
I have attached the original Vodafone Australia i9100T modem.
Modem is I9100TDUKF2.
Confirmed working here. Flash using ODIN.
Please flash on i9100T I do not know if it works on the i9100.
Do NOT flash on a standard i9100 from what i know of this.