Just wanted to report that the function does not work perfect. The problem is with keywords - RGBStock imports only those keywords which are visible on the SXC site, not those which are really under the picture (in the edit mode).
The result? I have a lighthouse in Swinoujscie on both SXC and RGB. On SXC I can find it as "lighthouse". On RGB I couldn't do that... :( Cause "lighthouse" was not imported...