Question : seamless redundant internet connections

We have a relatively complex network at a SMB client.  The customer is looking for a high-availability internet presence with respect to remote users (both internal users and external users) being able to access their services (web, exchange email, VPN, ftp, etc) when their internet connection fails over from primary to secondary.  

They already have the network infrastructure behind the internet connection.  Internet connection fails from providerA to providerB without any problem but when it does, the IP Address scheme obviously changes with providers.

I know DynDNS and the other similar vendors out there can handle a single public IP Address but we have multiple services hosted behind multiple public addresses.  I need each respective service to fail its DNS record from ProviderA.Address1 to ProviderB.Address1 and ProviderA.Address2 to fail to ProviderB.Address2 when the ISP failover happens.  

Anyone have any suggestions on what I can do to ensure that the mail.company.com, ftp.company.com, remote.company.com, extranet.company.com, etc. all fail to their respective IP addresses at providerB when providerA fails?  The IP Addresses fail already without flaw.  The names are where I'm having the problem.

Answer : seamless redundant internet connections

Instead of getting public IP from two seperate ISP, i reccomend that u go in for Regional Internet Registry that allocates IP like APNIC for Asia Pacific region. In doing so ur IP address will not be dependant on one ISP and can failover seemless with correct protocols enabled on ur routers.

The negative part of this is that, u will need to change the existing public IP to new ones and will have to re-do ur DNS entries too.