I would suggest you to use the USB-UART bridge in the Kitprog.
Use an UART bootloader with Tx and RX connected to P12_7 and P12_6 on your -059 KIT, these are internally connected to the bridge.
When the Kitprog is connected you will see an (emulated) com-port on your PC. This you may use for bootloading. Care for all the same baud-rate.
I tried that. Baud rate, security key, everything. I even checked and unchecked all of the Bootloader commands but still no. Weird thing is when I use a third party serial communication tool(Docklight), I can talk with the device...
Can you post your complete project (Bootloader and Bootloadable), so that we all can have a look at all of your settings? To do so, use
Creator->File->Create Workspace Bundle (minimal)
and attach the resulting file.
Can you please verify if you have programmed the Bootloader project to the PSoC5LP device. If not please program bootloader.hex and then try bootloading.