UART CDC FLOW PINS

Hi there!
I'm here for some days, spending some hours by day looking for how could I insert the logic for flow control by pins.
It is a little strange, I know, but I'm used to using ARM-LPC+STM and microchip pic 16 bits.
I have made some "sleazy tests", as it were...
And I could see that it is possible with a simple adaptation, convert the DAPLink to an ARM, PIC, 8051, AVR programmer.
For it, it's very necessary get the line signals: CTS, RTS, DSR, DTR.

I'd like to know whether someone in here would like to catch it up with me, and creating a universal interface!!
As it carry on, we can create a new chain.

Thanks a lot!