32:9 resolution on Precision 3550 with WD19

I have a 49" monitor with max resolution of 5140x1440 however when I plug it into my WD19 docking station using DP1.4 cable my only options are for resolution are 16:9 formats. Is there anything I can do to get this functionality? I'm concerned that this is because the display is being driven by the integrated graphics instead of the p520 discreet card. As a secondary question: Is there a away to force the use of the discrete graphics? I've chosen it from the Nvidia control center under manage 3d settings and Set PhysX Configuration, but it still seems to use the integrated graphics? I don't see an option in the BIOS either?