Repair Upper Rack Roller Kit

[FONT=Arial]I’m trying to replace the upper roller rack assembly–it’s the part that the rollers attach to (picture attached). I’ve removed the upper rack, pulled the unit from the under the counter however I CAN’T FIGURE OUT HOW TO UNSCREW THE ROLLER RACK ASSEMBLY FROM THE OUTSIDE OF THE UNIT BECAUSE IT IS ENCASED IN PLASTIC.

How does the assembly unscrew from the dishwasher unit? Thank you for your help. [/FONT]