dear ars, 
               first of all its good question here is my few cent yes u can showing ur passport to the bank usually what i do is i use my credit card and pay to thamel.com and they will give me nepali rupees and i spend nepali rupees like there is no tomorrow but that is for buying nepali rupees for dollar . about rupees to dollar i think  may be u can may be showing ur passport to bank  .
                            
                                                                       
                                                                                                 Yours Sincerely,
                                                                                                  Intelligent guy