The belts firat used by Ducati were constructed with steel braiding woven in them for strength. These weren't the "best" ones for the job. The tight pulley radiaii mentioned above were the main problem. They didn't lat too well. They were replaced with a belt using Kevlar as the reinforcement. This is stronger and far more flexible. You can spot them because the writing on them is red in colour. The earlier steel belts had white writing. It's very doubtful you'll see any of the old belts now. Ducati haven't used or sold them for years. Some of the belts offered up as "alternatives" to buying them from Ducati are steel ones though, so be careful if you think you're saving a few quid.
Just so that you know I'll be following my own advice.
There's a ride out on Sunday and ideally I'd be using my ST2 to save getting my 888 grubby.
But the ST was due a service in October to change the 2 year old belts (that's their service life), but because of all the personal crap I've been through in the last 6 months I haven't got round to getting the bike serviced yet, so I won't be using it until I do.