SAM7X EMAC TX_ER

Hi! Maybe my question is not really FreeRTOS specific, sorry for that. I picked up FreeRTOS and lwip running on SAM7X for my coming project. Purchased sample board, tried it out etc. Works fine. As I started to design my own board I decided to change the ethernet phy to Micrel KSZ8041NL as its good price, availability quite ok and small package (32pin QFN). But despite of its said to support MII interface (as SAM7X), it lacks one signal: "TX_ER". All the other phy-s seem to have this additional pin (but have bigger package, higher price etc). And the worst thing is that I didnt understand if this pin is really needed for FreeRTOS/lwip application to work (without compomising somewhere, and if, then where?) or not. Could you please help me out with this so I can proceed with my HW. Im currently planning to enable this pin as general purpose IO and use it for different purpose (as phy does not have it). Thanks, Madis