There is a need to include remote server IP in the reports.
It is stored in "r-ip" Access Log field, but official Reporter documentation doesn't mention this field as supported one.
Reporter ver. 11.x
Starting from ver. 11 Reporter is ready to accept the "r-ip" Access Log field which represents the remote server IP address.
This can be verified by expanding the available columns list in the Full Log Details report:
Until this field is added to Access Log format on Proxy, in Reporter it's displayed as "0.0.0.0"
After the field is exported, the Reporter shows actual Server IPs.