ROO web mvc conversion error

I created an entity, "Tasa" with a BigDecimal field.
When I try to save a new "Tasa", with some decimal value like 12.30, the server says that "The request sent by the client was syntactically incorrect ()."
Looking at the log I found:

Failed to convert from type java.lang.String to type java.lang.Long for value '12.30';

How do I force spring to convert to BigDecimal instead of Long ?
Regards
Emilio

Answer to myself:

If your entity has the same name as a field of that entity, it will FAIL
try next script

project --topLevelPackage test --projectName test --java 6 --packaging JAR
jpa setup --database HYPERSONIC_IN_MEMORY --provider HIBERNATE
entity jpa --class test.model.Cuota
field string --fieldName name
field number --fieldName cuota --type java.math.BigDecimal
field string --fieldName surname
web mvc setup
web mvc all --package test.web