Resolution:
According to "TIBCO Enterprise Message Service User's Guide" -&gtChapter 2:
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To set message compression, the application that sends or publishes the message must access the message properties and set the boolean property JMS_TIBCO_COMPRESS to true before sending or publishing the message.
Compressed messages are handled transparently. The client code only sets the JMS_TIBCO_COMPRESS property. The client code does not need to take any other action.
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In BW, a JMS property is set  using JMS Application Properties activity.
Steps:
1) Add a JMS Application Properties component with one field, JMS_TIBCO_COMPRESS, with a Boolean type
2) Create a process with either JMS Topic Publisher or "JMS Queue Sender"
3) Refer the above application properties in JMS Topic Publisher through Advanced tab
4) In the input tab, under OtherProperties complex element, specify a value of 1 (true)