Problem with client certificate and HTTPS Inspection

Dear All,

Server: Windows Server 2008 R2

Application: TMG2010 Standard

Function enabled: HTTPS Inpsection

Problem:

TMG is in a workgroup serving as a web proxy for domain PCs to access Internet. I use a USB token (with certificate) provided by bank to access online banking, the TMG log shows error code 80090326 and the message "This page cannot be display" on the PC when trying to logon banking with CA option. This happens when HTTPS inspection is on, and no access problem when HTTPS inspection is off.

Since it is a requirement that HTTPS Inspection must be enabled, is that be design that TMG in workgroup does not support client certificate?

I have searched on the web with the following articles, but still not sure if it is by nature or we can have workaround to solve it?

https://technet.microsoft.com/zh-cn/library/ee796231.aspx#u56fdssd

Some solutions found on the web, but not sure if they capable for my situation.

https://support.microsoft.com/en-us/kb/982550

https://social.technet.microsoft.com/Forums/forefront/en-US/16ff2286-ef07-4127-9887-69f8651e226b/https-inspection-connection-problem-using-sp1-update-1-rollup-3?forum=Forefrontedgegeneral

Any thoughts can be shared?

Best Regards

Ben