SSAS 2008 - Possible to define a default value other than 0 or blank?

I have an ISNULL function for a keycolumn in the view that feeds data to a dimension. Is it possible to achieve something similar but using the cube processing ErrorConfiguration at the Dimension or Partition level? Basically, what I want to accomplish is that whenever a dimension or partition is processed, if a columnkey has a NULL value, replace it with a -1 vale instead. I know if I setup the ErrorConfiguration Unknown Member it will default to either 0 or blank depending on the data type but I would like to have it default to the -1 value instead.