variable-sized data into fixed-sized data?

Hello,

I read from this document: http://blogs.mathworks.com/seth/2009/10/16/radar-tracking-in-simulink-variable-size-signals/ that variable-sized data can be converted into fixed-sized data, but I tried several times and it didn’t work.

The model consists of following blocks: A multiport switch block outputs variable sized data from two vectors of different lengths (3x1 and 4x1). The U port of Assignment block is connected with this switch. A vector [0;0;0;0] is connected with the Y0 port of Assignment block.

The Assignment block is configured as:

Number of output dimensions = 1 Index Option = Assign all

I get an error: The dimensions mode of input port U in 'Assignment' does not match the expected dimensions mode based on the dialog parameters and the dimensions of other ports.

I searched for this answer so long in Google but found nothing. Please help me if you can. Thank you very much.

Senmeis