Hi David and Ivan,
These types of steps are created using the same type of process that you would use for regular textbox input. Record the step entering in some data into the appropriate RadInput field and the test step will be created in your project. After the test step is created, highlight it and then go into the Properties for the step, and then add the binding reference for the appropriate database.
In the provided example, Pavel used the "BuildInGrid" instead of binding an entire database (this way there is no need to include the spreadsheet, the test will run with the .aii and .resx files present).
If you try to type into the RadInput field while recording, does WebUI not record the test step for you to manipulate? Please let us know if this is the case so we can look closer at the RadInput setup you have for your Dev environment.
All the best,
the Telerik team