SQL Server 2008R2 Ent + Win2003 Ent R2 32bit will not use all available memory Server:

HP ProLiant DL380 G5
2 proc -2x QuadCore Intel Xeon E5450, 3000 MHz
Memory- 12288 Мб (DDR2-667 Fully Buffered ECC DDR2 SDRAM)


Settings:

/3GB in the boot.ini. 
/PAE in the boot.ini. 
Enabled AWE in SQL Server.
Enabled Lock Pages in Memory Option for users SYSTEM and Local Service. 
Set Min/Max Memory to : 6 Gb/8 Gb


SQL Server: Memory Manager_Total Server Memory (KB) = 100%

I don't know how to make SQL capture free memory allocated him.
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.