The SWD pins of Miniprog4 are dedicated to SWD functions. These pins can not be used to support I2C functions.
The I2C pins of Miniprog4 are dedicated to I2C functions. These pins are provided at the 6x2 connector. These are the pins that support CapSense programmer. You'll find this information in the Miniprog Kit Guide (installed with Creator, documentation).