Well now, this seems morbidly interesting.
I get these as well, not nearly as vivid though. Flashes, dreams, but not full on visions. The one thing that distinguishes "past-life visions" are the details. Many people I've worked with have told me that they've seen lives where they're soldiers, or gypsies, many other professions... but not one could describe to me a single detail about the world surrounding them. Nor could they describe the look on people's faces.
When I get my little flashes, I usually draw them out (to the bet of my abilities, since I am no artist). And in the few times I have, I've come across people wearing black silky robes with stitched in characters, nobles wearing purple floral laced pattern shirts, and even myself in younger years.
The problem with these visions is that while I can describe them, I can't confirm anything because I don't know who these people are, or if they even exist.
Did you hear a voice, or did you just see the solider and yourself? What was he wearing? Describe his face if you can.
If it truly is a past-life vision, not once have I ever been able to will them to come around, most times they happen at random. A single motion could trigger a memory at random for me. Then again, small details can lead me to know more about people after I've met them. Things not even they know.