problem with UART1.

Hi all.
Need help with uart1.
I test demo UART (is use UART0) and work good, but if change UART0 to
UART1 not receive data and dont work interupt . Sending is work but no
receive.
On data sheet is write so UAR0 is same like UART1 but UART1 have modem
control line.
what is wrong???

demo UART is on
http://www.siwawi.arubi.uni-kl.de/avr_projects/arm_projects/lpc2k_bundle_port/lpc213x_lpc214x_examples_20061205.zip

regards