There is one, let the shadowcaster hover flat just a few units above the ground ^.^ And stretch and rotate it to create your desired shadow.
Something like this here, he has two shadowcasters for left and right, i just would turn off the unneeded one:
An even better approach might be to use different Lightchannels for your Mainlight (channel 0) and for a separate shadowcaster light (channel 01), and let your normal sprite react only to the main light channel, and the shadowcaster only to the shadowcaster light channel 01.
Your environment then just have to react to both light channels to get affected by the shadow created by the light with channel 01.
of course, you then have to adjust your lightintensities of your scene, so that both of the lights combined do not get to bright. But that is doable with some finetuning 
The big difference is, that with this method your environment reacts properly to your desired shadows.
