Environment Variable to set for tuning load jobs in BW

[saadmirza]

Hi All,
I have the BW Load pack documentation saying that :
change the following environment variables in DS admin.

ASC_BWLOAD_IPAK_TIMEOUT for chaning the default timeout period from 120 to 180.
But I do not find any such variables in Administrator.
Should I create a custom variable and include the value in it?
Please advice as to where should I set the value.

Thx,
SM