Oracle Trigger Problem

Installing a oracle repository with nuxeo 5.3 DM the trigger NX_TRIG_FT_UPDATE doesn't compile.
the error is : PLS-00560: character set mismatch
on the statment trying to move a NCLOB content in a CLOB

this issue is related to isssue #NXIDE-22 but i created this new one because i tried to modify the trigger code
by hand to bypass the problem, but the application recreate the trigger at startup
so the problem become blocking for us