Linking fact table with a dimension having missing values - SSAS Multidimensional

Hi, for a my SSAS 2008 R2 cube I've a dimension with few missing values, that it these are present in the related fact table but not in the dimension.

In a such scenario, the processing operation failed saying that the dimension hasn't these values.

Is it possible to force the processing as if between fact table and dimension table exists a left join relation and not an inner join?

Thanks