Problem with alt_2p5g_phy and polarity inversion.

We are using Altera alt_2p5g_phy  with a fixed clock of 2.5Ghz.

We need rx and tx polarity inversion in our set up.

Unfortunately the GUI to set up the phy does not allow to modify the polarity.

From the documents of the phy it is clear that this functionality is available.

Is there a way to enable the inversion?

Thanks in advance for any help.