Exchange OWA not in one domain

Hello,
We have 2 exchange server exch_01 and exch_02 with OWA installed on it they are both PDC and connected via trust relationship and site connector. Only exch_01 is directly connected to internet. What i wanted to do is to check my email on exch_01 since it’s connected to internet and i can check my email anywhere.

Some info:
server 1
servername: exch_01
domain : PDC_01
i.p : 207.010.xxx.xxx – external
i.p : 192.168.xxx.xxx – internal
server 2
servername:exch_02
domain : PDC_02
i.p : 192.168.xxx.xxxx

Thanks in advance.