I don’t think you can do that via TEM. For TEM to work it’s magic, I believe there needs to be a TEM Client installed on the endpoint, which would make it a Managed Asset.
Under Edit Computer Settings … Choose the ADD button. Create your Setting and give it a value.
I’ve done this with Fields like …
ContactName
ContactPager
ContactPhone
Owner
The setting change is sent to the system like an Action and the value will be set as soon as the client picks it up. In Windows, it’s stored in the Registry key [HKLM\SOFTWARE\BigFix\EnterpriseClient\Settings\Client{setting name}]. Keep in mind that this would be on a 32bit system, 64bit systems store 32bit settings under the Wow6432Node. Other OS’s use different locations. You might consider creating an open ended Task that looks for systems that DO NOT have the setting, and have it set a default “UNKNOWN” value rather than getting an error back if you try to query it.
The relevance for that kind of task would look something like
not exists setting “AssetID” of client
and the action would be
setting “AssetID”=“UNKNOWN” on {now} for client
.
Another option is to use the comments field under the computer details tab to fill in your custom info though most customers will use Tim’s method described.