Primer extension

[Mikulskis A]

Dear Netters,
I have problems in promoter mapping because of false stops of reverse 
transcriptase (AMV). Computer analysis shows that most of stops appear in 
the predicted loop(s) of template RNA. Is it possible somehow to eliminate 
undesirable structures of RNA during the primer extension? Can I use 
formamide for this purpose or other destabilizing agent? What is the upper 
thermostability limit of AMV? I would like also to know if reverse 
transcritase can start extension from RNA-RNA priming? Where I can find 
more information about different characteristics of AMV?
Thanks in advance for any help, Alvidas.