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如图,已知直三棱柱\(ABC-A_{1}B_{1}C_{1}\)中,\(∠ACB=90^{\circ}\),\(E\)是棱\(CC_{1}\)上的动点,\(F\)是\(AB\)的中点,\(AC=BC=2\),\(AA_{1}=4\).
\((1)\)当\(E\)是棱\(CC_{1}\)的中点时,求证:\(CF/\!/\)平面\(AEB_{1}\);
\((2)\)在棱\(CC_{1}\)上是否存在点\(E\),使得二面角\(A-EB_{1}-B\)的大小是\(45^{\circ}\)?若存在,求出\(CE\)的长,若不存在,请说明理由.