Expiration of messages in Queue + OSB (part 2)

Question

I am working on a prototype and I have the following scenario :
I have on ALSB (OSB) a JMS based Proxy Service that uses a queue in order to get the messages.
On the queue are put SOAP messages that are secured on message level.
There is a digest expiration on Domain Level that is set to 300 ms by default.
This means that the message once is created and reach the proxy it has to be in this 300 ms time frame.
==> Queue ==>Security Check on JMS Proxy Service ==> Message Flow
Problem nr 1)
In peak time i estimate that since on the queue to have maybe more then 1000 messages and 300 ms would not be enough.
If i modify this digest expiration on Domain Level i affect the other applications that are deployed also on ALSB (OSB) and i expose them to security breach.
Is there a way of solving this ? 300 ms is too small for such thing....
Problem nr 2)
The message pass the proxy (the security on message level) but in the message flow due to some exception (various reasons that are not important now) the transaction is rolled back and the message "is put back on the queue".
Now is the funny part: BEcause of the Digest Expiration Time which is very short the message for sure will expire until the redelivery (ususaly minutes) will be done.
So why a messages that already passed security is checked again on retry ? Can't this be avoided somehow ?
Thank you.

Answer 1

These question look like they are very specific to OSB, rather than basic JMS -- which has no concept of message level encryption -- I suggest reposting to the OSB newsgroup instead.