I have to make a correction to my last problem.
When RadTac is authenticating jusers in NT-domain MAR, the same NT-domain where RadTac is located it works with jusername that is 4 caracter.
But when RadTac is authenticating users in NT-domain STO (domain MAR and STO have two-way trust with eatchother) it only works if the username is 5 char. or more.

Yes Work :-)
Please control your setting. You can read more information on English manual of RadTac.Please verify if you use GlobalGroup and not Local Group and if match the Name of Group in NT and RadTac.

We use NT Modality all day in local my installation.

Thanks for your question
Giuseppe Giardina