A set of equations are put into a code forming a procedure to derive intensities of fluorescence lilies based on both physical properties of the fluorescent plasma and its location relative to the origin of the pumping emission. In a first test, the code is applied to symbiotic stars, and effort is made to explain the circumstances under which the two known Fell channels pumped by C IV are activated. For the channel at 1548.204 angstrom, which is most frequently observed to be active, there is a good agreement between the results of the calculations and the observed Fell line strengths. Fluorescence lines resulting from pumping through the other channel at 1548.411 angstrom can occur, according to the results of the calculations, only in the systems where a fast outflow from the white dwarf wind is present. The evidences of the white dwarf winds are found in the literature for all the symbiotic systems in which observation of the Fell fluorescence lines from the w(2)D(3/2) level is reported.