Texting Internationally and Boost Mobile

[Pooobaihr]

Ok...  do any of you know how to text internationally??  My Boost Mobile phone WILL NOT text to a friend that I have in Japan.  I have texted him MANY times.. and I have also contacted Boost Mobile customer support and they have said my phone should be working fine....   I dial  + - 81-80- xxxxxxxx   and for some reason.. I cant get through to him... BUT.. he can text me...  what kinda mess is that??  Do any of you know what I could do in order to get this right??  Is it my phone or is it HIS phone ??