Check that your second audio sequencer is compatible with Live 8.
Run and launch Live 8 if you haven't already done so. Live's rewire engine will install automatically with the rest of the program.
Close Live 8.
Launch your second audio sequencer and load a new project. Then, launch Live 8 again.
Follow the advice given in the instructions or help section of your second audio sequencer. Activate a rewire slave channel and select Live 8 as a slave input. The method for doing so will vary depending on the sequencer you're using.
Select the desired rewire "Bus out" in Live's output menu. Live is now connected as a rewire slave to your second audio sequencer and will sync to its tempo and transport commands.