You can use Set Data to write ICE attribute values to custom parameters (and Get Data to go the other way).
For example, you can use ICE to get the length of a curve and then store the length in a custom parameter.
Note: This didn’t work when I used the name “curve_length” for my custom parameter. The custom parameter value never changed.

Hi there,
I had trouble getting ICE to set the values of a custom parameter, did you find any way to get this to work?
Pete