The VIA chips run fine off passive cooling, they are a very low heat producing chip. You temps are coming from the fact that the Shuttle has very little airflow flowing thought it.

What kind of temps are you getting? 50's? Thats probably to be expected with the low airflow of a shuttle case. You may want to see if you can increase the airflow in you case, or maybe a small fan on the VIA.

But to answer the question, yes, the VIA's are actully made to be passivly cooled