.NET RIA Services - work with custom data layer
There is a web-application that works with Business Logic Layer (BLL). The BLL gets data from the Data Access Layer (DAL). The DAL gets data from DB through and does custom mapping.

At the moment it is required to add into the web application some functionality that will be Silverlight-based. It is planned to use .NET RIA Services for this purpose. 

In the demo-video (http://silverlight.net/learn/videos/all/net-ria-services-intro/) things are very well explained:
1st we need to create an entity data model (using EF, for example);
2nd we need to create a domain service using earlier create data model as data context.

I guess it is clear that it will be not a very good idea to start EF usage as data context in my case: this approach will require to work with the DB data directly skipping DAL and BLL logic.

Could you please advise:
1. What is a better way to get SilverLight functionality on my web-site: to use RIA servicec or better to skip RIA services, implement own WebService that will provide the data, use this WS from the SilverLight app directly)?
2. If we still are going to use RIA, how to create a data context that will use BLL as data source?

Any other ideas or thoughts are welcome.

Thanks.
.NET RIA Services - work with custom data layer
===

There is a web-application that works with Business Logic Layer (BLL). The BLL gets data from the Data Access Layer (DAL). The DAL gets data from DB through and does custom mapping.

At the moment it is required to add into the web application some functionality that will be Silverlight-based. It is planned to use .NET RIA Services for this purpose. 

In the demo-video (http://silverlight.net/learn/videos/all/net-ria-services-intro/) things are very well explained:
1st we need to create an entity data model (using EF, for example);
2nd we need to create a domain service using earlier create data model as data context.

I guess it is clear that it will be not a very good idea to start EF usage as data context in my case: this approach will require to work with the DB data directly skipping DAL and BLL logic.

Could you please advise:
1. What is a better way to get SilverLight functionality on my web-site: to use RIA servicec or better to skip RIA services, implement own WebService that will provide the data, use this WS from the SilverLight app directly)?
2. If we still are going to use RIA, how to create a data context that will use BLL as data source?

Any other ideas or thoughts are welcome.

Thanks.