Expression pedal without expression port

[Hanhom]

Hello there!

In the coming months I will play keyboard at a concert using MainStage.
A lot of the patches need to switch instantly and I wouldn't have time to fade stuff in and out by hand. Let alone free hands! An expression pedal would be really helpful in these situations.

The only problem is that my keyboard (Nektar Impact LX61+) doesn't have an expression port. Derp.

I've looked around the website but I'm not sure I understand:
Is any of the devices capable of 'splitting' my sustain pedal port into a sustain port + expression port?
Or any other tips on how to solve this problem without having to buy a new keyboard just for the expression port?

Thanks in advance!
Hanneke