Many thanks for your post, although I am not entirely sure what you are looking for I am afraid.
SQL Data Generator will generate a date / time which is random on any column that uses the datetime datatype. From here, you can then choose the minimum and maximum date and select to randomize the time, without the need to use a regex.
Red Gate Software Ltd
+44 (0)870 160 0037 ext. 8569
1 866 RED GATE ext. 8569