You could try here. I found this association while looking for something else:
Diane Reddy Secretary WWII War Brides Association PO Box 1812 El Centro CA 92244-1812
For Questions ask Erin:
If she had the serviceman's exact name it would help. Can she get the parish or church records and find out the man's name? Also, a consulate or other civil office there in Belgium may be able to help, as Jeanne would have needed a passport or other travel docs to get to the US.