Indexing for Oracle Text

Hello,

I need to index a column of type BLOB, containing html text data as well as pdf and word documents. The indexing wasn't the problem, but now I'm trying to find a way how to get Oracle to search without considering the case of the the text (case-insensitive).
Unfortunately I can't just say: ...WHERE CONTAINS(UPPER(columnname), 'searchString'.....
because the upper function doesnt' support blob, and besides, it wouldn't work anyway, for some of the data is saved in pdf format...

Thus, I guess the only possibility to do a case-insensitive search would be to index the column in lower case, right? As for now, I'm using the Oracle INSO Filter. But how can I additionally filter the columns (*after* those having run through the INSO filter), so that the index merely contains lower case text?
I'm thinking of Oracle's procedure filter, or user filter, but I don't exactly know how one can apply multiple filters (INSO + lower-case filter)... - does anybody know how to accomplish this? Any ideas would be appreciated :)

Thanks in advance,
Can

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Can...
http://pdf.natune.net


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