The halo neutron pair pre-emission in Si(11Li, fusion) has been investigated. An approach based on Monte Carlo simulation for identifying the true n-n coincidences against cross-talk has been worked out. Experimental evidence for residual correlation of the halo neutrons was found. The results obtained in building the n-n correlation function by using the available denominators and procedures are discussed. An experiment for getting with good resolving power the intrinsic n-n correlation function is proposed.