have you try it with this drivers?
This USB Driver is used for connecting your Motorola handset to a 64-bit Windows computer via a USB cable.
Download the drivers at
MOTODEV
Supported Handsets
A630, A845, C380, C381p, C381/C386, C384/C385/C390/C391, C650/C651, C698p, E375, E398, E550/V535/V560, T725, V180/V185/V186/V188, V220/V220i/V226, MOTORAZR V3 (CLDC 1.0)/MOTORAZR V3b, V300/V400/V500, V330/V547/V551/V555, V303p/V400p, V540/V550/V545, V600, V600i, V620, V635, V80
C975, C980, E770, E1000/E1000R, E1070, MOTORAZR V3x, V975, V980
L2/L6/L6i, PEBL U6, MOTORAZR V3 (CLDC 1.1), MOTORAZR V3i/V3e/V3t, MOTOROKR E1, MOTOSLVR L7, V190/V191, V195/V196/V197, V230/V235, V360/V361, V365, V557/V557p
MOTORAZR maxx V6, MOTORAZR V3xx, V1100
MOTOKRZR K1, MOTORIZR Z3, MOTOSLVR L7i/L7e
A760/A760i, A768/A768i, A728
A780, A910, E680/E680i, MOTOMING A1200/A1200i/A1200r, MOTOROKR E6, MOTOROKR E2
System Requirements
Windows XP 64-bit or Windows Vista 64-bit
You must have Administrator permissions to install this driver
Notes
Please reboot the system after installing this USB driver
Installation of Motorola’s Mobile Phone Tools may affect the performance of this driver. Please re-install the USB driver after the installation of the Motorola Mobile Phone Tools