Even if all of the load combination generation formulas are implemented in ConSteel for the automatic generation of combinations, standard formulas may not cover every necessary combination cases.
Of course, in this case, it is possible to define the missing combinations manually, but it is very likely, that the missing combinations are available, probably in a table form.
It is good to know, that ConSteel is capable to receive combination data, by the good old CTRL+C & CTRL+V method. If you have the factors for load combinations stored in table form, stored for example in Excel, just copy the data of the factors to the clipboard by CTRL+C, and then CTRL+V paste them into ConSteels's load combination table:
Of course, it works in the other way too, combination data can be copied to the clipboard from ConSteel by pressing CTRL+C and pasting it into spreadsheets by CTRL+V!