Resizing partitions not an option
When the Live CD is booted and the installation gets as far as the "Installation type" dialog, there is no option to resize the existing partition or install along side it. Instead there are only three options : "Upgrade...", "Erase...", and "Something else" It's not a matter of the partition not being found. The dialog does say "This computer currently has Ubuntu Saucy Salamander on it. What would you like to do?" and it does offer to upgrade. It's just that the resize option is missing.