How to partition SD card on Android 4.1.1 using Linux?

Hi I have a HTC Desire X and this device has a SD CARD with 16 Gb. I want to extend my memory using Link2D. I read I have to make partitions on my SD Card. The problem is that I do not know how. If I connect my phone in debugging mode with my Linux Mint laptop, it will connect with MTP and therefore I cannot use a partitioning tool. The Team Win Recovery Project Partitioning Tool (2.5) fails while partitioning the card and installing the app "APparted" or a busybox fail as well. How can I partition my SD card in the phone using Linux or Android? The phone is rooted and SU is installed.