1995 750iL Car Phone/SIM card Issue

Hi Everyone!

I'm brand new to this forum, and indeed, brand new to owning a BMW! Very excited! I've recently acquired a 1995 BMW 750iL - It's in great condition, with only 124,000 Kms since new, and is Navarra Violet in colour. From what history I have gathered, it was a Japanese consulate car in Tokyo, before finding it's way to Australia in the early 2000s.

I love the (numerous) features of the car, but I'm having trouble with the (very cool) car phone. I purchased a pre-paid Telstra SIM card for it, and activated the SIM, but when I insert it into the car reader under the handset, the display on the phone reads "Check Card"... I've got no idea what to do. I've read that some E38s have another SIM reader in the boot, next to the CD stacker, but my car doesn't have GPS/Sat Nav, and as such, I can't locate this mysterious second card reader for the life of me. Does anyone have any suggestions/has encountered similar problems? The phone is a GSM network-based handset, so by rights it should work fine. Could it have to do with the car being Japanese in origin originally, and thus the handset won't work here? Are the handsets fussy with which provider you use? I asked my local BMW dealership, but hey had no idea whether it would or wouldn't work - they directed me to asking my service provider, Telstra, who claim that the handset should work without any issues.

Thus, this leads me to think that perhaps I'm the problem! Is there a trick to getting them to work? Any help would be very much appreciated, as I'd really love to get the phone working! Looking forward to being an active member of the forum! Thanks in advance