Using a function handle in the cost function

I’d like to minimized the following problem:

minimize( norm( R*x, a ) ),

but rather than having CVX calculate R*x directly, I’d like to supply a function handle that does it with a more efficient algorithm:

minimize( norm( fhandle(x), a ) )

Is this possible? I am getting complaints about unsupported argument type ‘cvx’ and have not been able to figure out how to cast x back to a double. I saw the section on using ‘expressions’ in the user guide but can’t see how that would help in this situation.

Edit: What if R is an object with the ‘*’ operator overloaded?

No, this is not possible. The list of supported functions given in the users’ guide is complete. No other functions may be used.