When you state "Thermal Parameter" are you talking about the power dissipation box?
The geometry information should be in the data sheet for the part. You may be able to get the "Pin Thermal Conductivity" info from the data sheet as well. For instance it might tell you what material they are using, then select it from the drop down box if available.
The "Junction to Case" entry I have obtained from the data sheet before. Sometimes it is stated, sometimes it's not.