+1 for this feature, and for adding segmented stats from those scales that have this (like the 'Ironman' ones).
As others have said, when you own Garmin products (I have 2 Edge devices) and products from their partners (we have Tanita scales) there really should be no issue :(
http://www.garmin.com/garmin/cms/home/support/searchsupport?src_url=http%3A//iqc.garmin.com/eCustomer/KODSelfService/request.do?create=kb%3Agarmin%26forward=escalate
I sent a request to support and I got the response back to post on the forum as the developers seem to monitor this.
+1 for me on adding manual input for the other statistics in the Health section. I have a Whirlpool weight scale that gives me weight and body fat measurements.
Ringo