so you are looking for a surface mount IDC connector to make a cable?
I have never seen those, I usually replace them as they did on later model 3 and model 4 Keyboards with a 90' angled 20pins male on the board, (as it is on the main board)
then use a female-female 20p IDC connector on the cable, that way you can disconnect the connector from the keyboard. Unless I am misunderstanding what cable you are replacing?
if you're replacing this connector
then make it easier and make it become
using a Male Pin Header Right Angle 90° Dual Row 2x10P 2x10 20P 2.54mm #110-20-38
or
IDC type Cable Male Connector Box Header Right angle 90° pin, without eject levers #330-20 2x10 pins, 20 pins Part No. : LHR20GB1 2.54x2.54mm pin pitch
then use a female connector on your IDC cable. as mentioned earlier so it's "removable" for future troubleshooting.