Well,
I bought a 2 wire charging cable, and sometimes although the power applet say it is charging, it isn´t, and the red LED doesn´t lit.
I tried different charging cables (regular charging and data cables, original from Motorola and other brands and no-brands and this charging only cable) with mixed results. I notice when I do power cycle the phone the things tends to be normal for a while, but after some Wazings and days of use, the problem arise again, and sometimes, power cycling doesn´t help until I use the supplied charger. So I guess the phone somehow knows where is plugged in.
Today I found this article, which makes me think my guess is correct, and I want to share this with you, guys:
How to make your own iPad 2 USB Charger (DIY iPad 2 USB Charger)