Adding Weapon Upgrade on a Blue Item..

If A blue item has no prefix on it yet but it was already identified, is it able to put an upgrade on that sword?

Lets say if the sword was identified only to have no prefix but a 10% damage (while hexed) mod and you planned to add another sword upgrade. Would the 10% damage stay there or would it get erased by the upgrade?

Any ideas?

Please.. someone.. anyone?

You should be able to upgrade it without removing the non-prefix/suffix stat. Even if it is going to overwrite it, you will get a dialog box warning you first, so you can still cancel.