Seemingly unrelated regression help

Hi, I'm using SAS OnDemand for Academics. I would like to know how to estimate a seemingly unrelated regression with categorical variables. Below is an example of my code:

proc syslin data=sas1.logtobacco1 sur; model div1=ltotexp tobdummy1 sex1; model div3=ltotexp tobdummy1 sex1; run;

Where tobdummy1 is a binary variable, marital1 is a categorical variable, div1, div3 and ltotexp are numerical variables.