How to set included parameters with flow variables?

As I see there is an option to set the length of the list of the included columns for the column filter components with flow variables. But it is not clear how I could set the proper list of the included columns. Is there a way to do this with KNIME 2.0.3? (I guess there is, but I have no idea how to do this.)
Thanks, gabor

Flow variables are single-value variables (scalars), there is no array type as of now. Modifying lists or arrays is therefore not (really) supported. Arrays, like the include or exclude list of the column filter node, are internally represented as an xml-subtree with n+1 children, whereby one field represents the length of the array and the remainder is used to keep the actual values. Currently these arrays are shown as they are, that is as subtree with n+1 fields. In theory(!) you should be able to shorten the array (just assign a lower “length” field and overwrite the first x entries that you are interested in) but you cannot enlarge arrays.

This is probably irrelevant for your current problem but I’d like to add that the “flow variables” tab was/is a generic feature to enable flow variables without touching the source code of each individual node (including partner nodes). It is very powerful but sometime also confusing, in particular for array types and for default dialog components. The NodeSettings objects that are exchanged between dialog and model were not meant to be displayed to the user initially. Variable support was added at a much later stage (v2.0). The user-friendly version of flow variable support is currently being added to some of the standard nodes. We decided to add little buttons to selected controls in the dialog, which then open a pop-up, allowing for variable support without loosing the context. Some of those will be included in v2.1, there is more work to do in the future …