Thanks for the speedy response, Alan.
To be clear: if memory serves SPSS lets you specify the reference value for a categorical variable. So for a variable with 0/1/2 values, you can specify '0' as the reference category.
However, if I understand you correctly, the method for PSPP is to create a dummy variable (0/1) for each of the 0/1/2 values and then exclude the dummy variable for 0 as the reference group. You can run additional models and swap out the remaining variables to change reference group.
Jack