Here's a normal command line sleep 1000 qbsub:
qbsub sleep 1000
This is how you'd do it with the --data and --type:
qbsub --type cmdline --data '(=(cmdline=sleep "1000"))'
I found the data string by running
qbsub --xml --export job.xja sleep 1000
Examining the job.xja file for the <data></data> pair shows:
<data>(=(cmdline=sleep "1000"))</data>
So you should be able to submit an miGen job, check the xja file in the job log directory for the <data> tags and use the contents as a template.