I will paste here the answer provided in the similar support thread.
We actually provide support for ordered associations. You just have to specify the sequence column name using the .HasSequenceColumn(string) after MapJointTable(). What we have changed is the default behaviour of Lists, as they should usually be mapped without an extra table.
Please try this out and let us know whether this works for you. If you face further trouble it would be best if you could provide us with a sample solution that we can use for debugging purposes.
I am looking forward to resolving this matter with you.
the Telerik team