SQL Server 2008R2 Ent + Win2003 Ent R2 32bit will not use all available memory
AWE memory can only be used for data cache. Things like procedure cache, workers stacks, execution memory grants, SQLCRL and so on can only use the process 'real' memory space (ie. the 3Gb). So even if you did set up everything correctly, it does not mean that 1) SQL Server will actually use all the 6Gb and 2) you won't run into out-of-memory issues despite plenty of AWE memory being available.

32bit is dead. Just move to a 64 bit environment and call it a day.