Silverlight

well hoping someone has some insight. .we have an application (API HealthCare) that uses silverlight. when it runs client direct to server it is fine. If I insert the F5 in between it doesn't work.. ends up with an application error. yet it works through a NetScaler (did I say a bad word?). What is going on? Note I have to get it to work through APM, but right now I have reduced it to a simple connection client > F5 vip terminate SSL, > server SSL. I'm going to try layer4 with no SSL termination to see if it works.. but that won't solve the problem.