Database use of char[>1] cause using Convert(x,x) and negates using an index

When a database defines a char of length greater than 1, a convert(x,x) is being used in the criteria, and thereby, negating the use of an index and causing table scans.

Note: There is no option to change the database schemas, because they are from a COTS product.

I would think there needs to be a solution in the translator such that if it can be detected that its for a char column and that it does not do the convert.