Japanese cell phone in Australia?

I live in Japan and have a spiffy new Docomo phone that I want to use in Australia whilst im on vaccation. I know about international roaming already....

To confirm my suspicions, I cannot just replace my Japanese UIM card with my existing Australian SIM card? Because the phone itself is locked to my Japanese UIM card?

I`ve read how some of the newest generation CDMA phones can handle GSM SIM cards, but regardless, until my phone is unlocked, its pointless to try....??

If I ask Docomo nicely will they unlock my phone ;)

Don't know much about Docomo phones but before even looking to unlocking your phone I say its more important to find if your phone supports GSM.

CDMA will be phased outin January 2008 I believe (Telstra being the last CDMA carrier).

It would be useless to unlock your phone if it does not support GSM.

If your phone is capable of connecting to GSM networks and is unlocked to use other carriers, you can try a Vodafone $2 prepaid sim card (around 220 yen) from Woolworths/Safeway (a big supermarket chain) to see if it works.

If the $2 sim card works in your phone you can return to the cashier to purchase credit . If it doesn't work, you lose 220yen (no refunds).

To confirm my suspicions, I cannot just replace my Japanese UIM card with my existing Australian SIM card? Because the phone itself is locked to my Japanese UIM card?

You're right.

If I ask Docomo nicely will they unlock my phone ;)

No Japanese carriers unlock their phohes (nor can they do it technically, either).