For my ASP.NET MVC application I've created custom validation attribute, and indicated that more than one instance of it can be specified for a single field or property:

[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = true)]
public sealed class SomeAttribute: ValidationAttribute

I've created validator for such an attribute:

public class SomeValidator : DataAnnotationsModelValidator<SomeAttribute>

and wire up this in the Application_Start of Global.asax

DataAnnotationsModelValidatorProvider.RegisterAdapter(
    typeof (SomeAttribute), typeof (SomeValidator));

Finally, if I use my attribute in the desired way:

[SomeAttribute(...)]  //first
[SomeAttribute(...)]  //second
public string SomeField { get; set; }

when validation is executed by the framework, only first attribute instance is invoked. Second one seems to be dead. I've noticed that during each request only single validator instance is created (for the first annotation).

How to solve this problem and fire all attributes?