[R-SIG-Finance] Mean-Semivariance (downside risk) Portfolio Construction

[Gabe Plaxico]

Hello Everyone:

Does anyone have experience in constructing a mean-semivariance 
portfolio using the fPortfolio package?  What I am really searching for 
is the ability to use my own arbitrary "mean", essentially constructing 
a downside risk portfolio (Sortino - 
http://sortino.com/htm/New%20Book.htm).  Typically done using the lpm 
solver option.   My attempts at constructing this portfolio with 
anything other than the true mean for each security ends in an error.  
If anyone has done something similar can you provide 
suggestions/examples?  Thanks in advance.