Updating Deski Report instance using SDK

Hi,

I've have developed an SDK utility to archive reports older than 365 days from BOXI Repository and store them as PDF documents on our SAN storage. I’m trying to figure out the best way to mark an instance as archived so that we are not reevaluating reports since most of our reports have over 1500 report instances. I’m currently updating SI_KEYWORD as ‘InstanceArchived’ but this is updating SI_UPDATE_TS, so the report instance date is getting updated causing confusion for end users.

Query criteria for archiving report instances -

strQuery = "SELECT TOP 5000 SI_ID,SI_ENDTIME FROM CI_INFOOBJECTS WHERE SI_PARENTID = '"

                     + iDocID + "' " + "AND SI_STATUSINFO = '' AND SI_KEYWORD != 'InstanceArchived'";

Thanks!