The following is based on the following blog post by Jerry Walter that describes how to use a property value to create annotation text as a new text feature.
http://communities.bentley.com/other/old_site_member_blogs/bentley_employees/b/jerry_walter_-_bentleys_blog/archive/2011/02/11/bentley-map-point-text-feature-pba
By default, the GSA uses a text sub-feature to define the placement of an PBA annotation. The text sub-feature is created when the features placement meta data is created. In the case of Point-Text features, this results in a placement dialog with a field for the Text String as well as the Value. The following describes how to eliminate the Text String portion of the dialog.
A simple text feature is created with a single property called Value. To change it so the Value property becomes the text being placed, the following changes are made.
The Symbology node of the feature is selected and PBA using Expression is added via the right click menu. This results in the Add PBA using Expression dialog which can be further edited.
The name is entered as PBA and the Expression is entered as the name of the property which in this example is [Value].
This change can be reviewed in the Symbology tab and PBA details pane:
The initial value for the Value property is set to a unique text string.
The metadata for the text feature is inserted as Place Text and Rotate. This will create the necessary Operations and Methods.
To complete the task, the methods and operations are updated.
The Place method is updated to set:
StringSourceType to PBA which is the name given to the Expression above.
StringSource to FeatureName/PropertyName which is this example is Text/Value
The Operations of the feature includes definitions for the Text String and Value in the placement dialog. Since the Value is the only item of interest, the Text String is deleted.
Once exported, the modified text feature should appear as follows:
The following principals can be used to modify Rich Text features as well:
A sample schema has been provided for your learning.
Text from PBA.zip