There are a few reasons why you were not able to find data for the stations in which you are interested.
First, the WMO ID numbers in the dataset leave off the last two digits (usually 00). So, if you are looking for station ID 28630000, for example, try looking for 286300 instead. Second, the names in the station lists are not all up-to-date for Russia. Some of the cities are listed by their pre-1992 names -- it is likely that the names in the official WMO list had not been updated at the time this dataset was put into the Data Library. Even in the WMO list from this year, Yekaterinburg is not yet listed, but rather, the old name of Sverdlovsk still is. So, when searching by name, you may need to search under the previous name for the city (Leningrad for St. Petersburg). Zlatoust, however, is okay.
--Michael Bell