Query Task URL too long

Hi,

 

I have buffered a large polygon and then need to use the geometry to query another layer using the query task. When I input the geometry, I get errors saying the url is too long. The geometry does have a lot of vertices but I can't change the size or shape of the polygon. I have read you can pass the geometry in via the custom parameters so it will bypass this issue. Is this the case? I can't figure out the format I need to enter to use the custom parameter. Does anyone have an example of how to populate the custom parameter in the query task to get around this issue?

 

Thank you!

 

Belinda