How to address the ports of the processor?

I address from the µVision program to the ports of the Teridian 71M6541FT processor by name.
The list of ports: SEGDIO0 - SEGDIO14 SEGDIO19 - SEGDIO27 SEGDIO36 - SEGDIO39 SEGDIO44 SEGDIO45 SEGDIO51 COM0 - COM3 SEG46 SEG47 PB VLCD VREF IAP IAN V3P3A VA TEST GND XOUT XIN VBAT_RTC VBAT V3P3SYS IBP IBN GNDD V3P3D VDD ICE_E SEG48 - SEG50 RX TX.

The compiler produces error. Error: # 20: identifier "port name" is undefined.

How to remove this error?

Example of the programm

int i;

void main(void)
{ i = SEGDIO24;
}