How to import libraries to Mist?

Question

I've create a contract in Remix imporing 2 differents libreries and it works ok, but when I copy and paste it into Mist I got an error at the import statement.

Code goes like this:

pragma solidity ^0.4.18;
import "github.com/oraclize/ethereum-api/oraclizeAPI.sol";
import "github.com/Arachnid/solidity-stringutils/strings.sol";

contract WeatherBet is usingOraclize{
    using strings for *;
...

Error msg:

Could not compile source code. 
Source "github.com/oraclize/ethereum-api/blob/master/oraclizeAPI.sol" not found

Thanks.