REX SED Help, need to replace namespaces from xml field

Hi,

I have a xml field which holds values like below. It contains namespaces for each element which I want to remove:

...message="<h:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<h:Header>
<h:creationTimestamp>2013-12-09T16:58:57.2450018+05:30</h:creationTimestamp>
<h:applicationId>XYZ</h:applicationId>
<h:hostName>Myhost</h:hostName>
</h:Header>
</h:Envelope>"

Obviously there could be more/different namespace values ("h:" prefix) in the the logs, so can't hardcode the value to replace it. I believe REX SED would be the appropriate method for my requirement.

I am very new to Regex so not able to start with REX SED command. Could anyone provide me some direction/example how to go about it?