I don't have a Optimus to test this on anymore so don't shoot me if it doesn't work. Just trying to help.
From my analysis of the problem...
If you boot into recovery or leave the phone off, it should charge.
If you are rooted and have Xionia installed, you should be able to do "mounts and storage"->"mount usb storage" (stay in that page after selecting, don't exit until you want to disable mass storage)
If you are rooted and want a quick way to boot into recovery Quick Boot from market works:
https://market.android.com/details?id=com.siriusapplications.quickboot&hl=en
These aren't necessarily great workarounds, but if you can't charge at all or can't access the USB from your PC to retrieve files and don't have a reader, it is better than nothing.
From my analysis of the problem...
If you boot into recovery or leave the phone off, it should charge.
If you are rooted and have Xionia installed, you should be able to do "mounts and storage"->"mount usb storage" (stay in that page after selecting, don't exit until you want to disable mass storage)
If you are rooted and want a quick way to boot into recovery Quick Boot from market works:
https://market.android.com/details?id=com.siriusapplications.quickboot&hl=en
These aren't necessarily great workarounds, but if you can't charge at all or can't access the USB from your PC to retrieve files and don't have a reader, it is better than nothing.