location of config parameter?

Hello,
I am sending a stored procedure
I see it in my log file:
dblib.c:1454:dbcmd(0xc71780, exec creerFede @LOGIN='3D1HfSkzgRZva_uT_TheSg==', @ID_SERVICEPROVIDER_TECHNIQUE='http://ts_saml2.msp.gouv.fr', @ID_SERVICEPROVIDER_FONCTIONNEL='http://ts_saml2.msp.gouv.fr', @ID_TYPE_FEDERATION=1)

I get an error in answer:
dbutil.c:86:msgno 103: "The identifier that starts with '@ID_SERVICEPROVIDER_FONCTIONNE' is too long. Maximum length is 30."

Does anyone know where to configure the size of this parameter?
I am using free-tds-dev0.92.

Thanks,

Loic



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