Lotus Notes / Exchange Server compatability issues when scheduling meetings

Hi first post here so hope that someone may be able to help me?

My company uses Lotus Notes as an eMail / Calendar package. The client that I face off to uses Outlook / Exchange Server.

We have noticed that when clients send us meeting requests from Outlook / Exchange they are received by and go into Lotus Notes correctly. But if clients reschedule a meeting we receive the notification message in Lotus Notes but it is not processed correctly - clicking the "Update Calendar" button has no effect and the meeting is not updated at all.

We have also noticed (and I think that these issues are linked) that when we use Nokia PC Suite to synchronise Lotus Notes calendars with the organisers in our Nokia phones all of our companies meetings (scheduled via Lotus Notes) are synchronised to the mobiles but none of the client meetings (scheduled via Outlook / Exchange) that we have accepted into Lotus Notes are synchronised to the mobiles.

Feels like an issue that would affect many companies and clients, thus something for which there should be published advice and resolution available on the web. But haven't been able to find such to date?

Thanks in advance,

Craig