tokenSession and execAndWait interceptor together

[himanjim sharma]

I'm trying to use tokenSession and execAndWait interceptor together
<interceptors>
<interceptor-stack name="searchformstack">
<interceptor-ref name="tokenSession" />
<interceptor-ref name="defaultStack" />
<interceptor-ref name="execAndWait" />
</interceptor-stack>
</interceptors>

but in some case when action execution time is bit a longer that wait page is displayed, this exception is displayed:
SEVERE: Could not find action or result
No result defined for action com.mmt.genericform.actions.GenericFormSeachServiceAction and result invalid.token
at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:363)

My guess is that as on wait page we have to refresh at fixed interval to see if action execution is complete, on any refresh token value is lost which leads to above exception.

Any suggestions regarding how can one fix this...