complex case statement in sql where clause : i have this code but i cannot make it work:

    	AND CASE DO11_DOCUM_MG36 WHEN 'TSC-ORDINE-RIC'
												   THEN 
												   (CONVERT(DATE,ISNULL(dbo.DO31_DOCCORPOORD.DO31_DATACONS,DATEADD(day,ISNULL(dbo.DO17_DOCTESTAPERS.DO17_NUMPERS4,15),dbo.DO12_DOCTESTARIF.DO12_DATAVSCONF)),102) <= '2016-02-29' AND dbo.DO12_DOCTESTARIF.DO12_DATAVSCONF is not null) AND (dbo.DO36_DOCCORPOEST.DO36_DATAST1 is null or CONVERT(DATE,dbo.DO36_DOCCORPOEST.DO36_DATAST1,102) >= '2016-02-01')
												   ELSE
												   (CONVERT(DATE,ISNULL(dbo.DO31_DOCCORPOORD.DO31_DATACONS,DATEADD(day,ISNULL(dbo.DO17_DOCTESTAPERS.DO17_NUMPERS4,15),dbo.DO12_DOCTESTARIF.DO12_DATAVSCONF)),102) BETWEEN '2016-02-01' AND '2016-02-29' AND dbo.DO12_DOCTESTARIF.DO12_DATAVSCONF is not null) 
												   END
Thanks