Samsung Galaxy S3 on Straighttalk -- Picture Mail Issues

[aj1981]

I recently acquired a Samsung Galaxy S3 and activated it on the Straighttalk network. Everything works fine but picture messages. I can send picture mail but I cannot receive them. It seems that since it is not a gsm phone, I do not have an APN menu. Instead I have to access the data menu through ##3282#. However, I cannot obtain my MSL code to change any of the settings. If anyone knows how to resolve this issue, I would greatly appreciate some assistance. Thanks.