I can convert may cluster/variant with 'Flatten To String.vi' to string. This string I save to DB.
After this string I can convert from DB Variant to string and after from string to original cluster/variant by 'Unflatten From String.vi'
It is working well. You can save to DB cluster with IMAQ Images.
I recommend use small table with 'cluster_ID'[int] and 'string_data'[text] ::: "Because SQL Server stores text/ntext columns on the Text/Image pages
separately from the other data, stored on the Data pages, it can
take more time to get the text/ntext values."
More details: http://www.databasejournal.com/features/mssql/article.phpr/2212141