Skeptics get it wrong on heartbeat location detection

I've been hunting for information on a military application of heartbeat detection tech to see people behind walls. This would be an amazing technology for the battlefield allowing soldiers to defend themselves from ambush.

The Skeptics Dictionary has a cutting piece. It seems the company may have used some poor business practice in it's earlier days.
http://www.skepdic.com/refuge/dkl.html
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the DKL LifeGuard was tested by Sandia Labs in April1998. The device failed to perform any better than expected by chance. In October 1998 Sandia took a DKL LifeGuard apart and found that the electronic components could not possibly function as advertised.

Whether in response to the Sandia tests or in response to increased criticism of their claims, I don't know, but DKL has changed its claims on its Internet site. It no longer features a collapsed building with the message that a DKL product would save the lives of those trapped inside. The featured come-on now is that the LifeGuard can detect stowaways on a truck. Also, the ads now say that the products can detect people, rather than heartbeats. It has removed some of its so-called scientific tests and replaced them with others, including one regarding the detection of stowaways on trucks.
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The critic claims to be an electronic engineer but seems to have forgotten what happens when you translate signals using Laplace or Fourier transforms (it's been over a decade since I studied Electronic Engineering myself so can't remember which of the transforms this works for). This sort of technology is used in submarines using DSP to detect different types of submarines and even different submarines because the transform makes it easy for digital processors to work out differences. It was used by a fellow undergraduate to detect heart and lung problems more reliably than any doctor could. They can detect whales too. DSP transforms pplied to this technology and other intelligent application of electronic engineering it's relatively easy to differentiate between friendly heartbeats and enemy ones.

This is the company that develops the commercial version and I'm sure they have military contracts for their technology.
http://www.dklabs.com/

Here's coverage of the successful use of the device in China to help find earthquake survivors amongst the rubble.
http://www.mcclatchydc.com/2008/05/20/37831/finding-quake-survivors-just-one.html

Here's a video of the device in action.
http://videos.mcclatchydc.com/vmix_hosted_apps/p/media?id=1890685

Geovox also have a similar technology which works on heartbeats rather than electrical signals though refinement is required for full utlity.
http://www.geovox.com/