A post-script to my previous post: A 2001 IRS document ("Who Must Pay Self-Employment Tax?", publication 533) at UncleFed.com says:
[Retired Insurance Agent
Income paid by an insurance company to a retired self-employed insurance agent based on a percentage of commissions received before retirement is subject to SE tax. Also, renewal commissions and deferred commissions for sales made before retirement are generally subject to SE tax.
However, renewal commissions paid to the survivor of an insurance agent are not subject to SE tax.
]
But I have not found this on the current IRS rules.
