Requesting the ability to Modify a Bentley Map feature in MicroStation.
MicroStation is not able to modify Bentley Map V8i (SELECTseries 3) features directly, due to XFM attribute constraints on the feature.
In order to resolve this issue, use Bentley Map's "Export to MicroStation Elements" command, found in the Command Manager. This tool was implemented for the new XFM data model in Bentley Map V8i (SELECTseries 3). Another option is to use the "Save as..." options in MicroStation, setting the Convert XFM Instances mode to 08.11.09.xx to 08.11.07.xx.
There are more details on using Export or Save as in the Bentley Map Help Documentation.