diff --git a/src/convert.jl b/src/convert.jl
index 5943e07b..ed96fb57 100644
--- a/src/convert.jl
+++ b/src/convert.jl
@@ -61,6 +61,8 @@ to_cxx_type(::Type{<:Tuple{A,B}}) where {A,B} =
     StdPair{to_cxx_type(A), to_cxx_type(B)}
 to_cxx_type(::Type{<:Pair{A,B}}) where {A,B} =
     StdPair{to_cxx_type(A), to_cxx_type(B)}
+to_cxx_type(::Type{<:StdPair{A,B}}) where {A,B} =
+    StdPair{to_cxx_type(A), to_cxx_type(B)}
 
 to_jl_type(::Type{T}) where T = T
 to_jl_type(::Type{CxxWrap.CxxBool}) = Bool
@@ -87,6 +89,7 @@ convert_to_pm_type(::Type{T}) where T <: TropicalNumber = T
 
 convert_to_pm_type(::Nothing) = Nothing
 convert_to_pm_type(::Type{Int32}) = Int64
+convert_to_pm_type(::Type{CxxWrap.CxxLong}) = CxxWrap.CxxLong
 convert_to_pm_type(::Type{<:AbstractFloat}) = Float64
 convert_to_pm_type(::Type{<:AbstractString}) = String
 convert_to_pm_type(::Type{<:Union{Base.Integer, Integer}}) = Integer
@@ -123,11 +126,12 @@ convert_to_pm_type(::Type{<:TropicalNumber{S,T}}) where S<:Union{Max,Min} where
 # convert_to_pm_type(::Type{<:Union{AbstractSet, Set}}) = Set
 
 # specific converts for container types we wrap:
-convert_to_pm_type(::Type{<:Set{<:Base.Integer}}) = Set{Int64}
-convert_to_pm_type(::Type{<:Base.AbstractSet{<:Base.Integer}}) = Set{Int64}
+#convert_to_pm_type(::Type{<:Set{<:Base.Integer}}) = Set{Int64}
+#convert_to_pm_type(::Type{<:Base.AbstractSet{<:Base.Integer}}) = Set{Int64}
 
 for (pmT, jlT) in [(Integer, Base.Integer),
-                   (Int64, Union{Int32,Int64,CxxWrap.CxxLong}),
+                   (Int64, Union{Int32,Int64}),
+                   (CxxWrap.CxxLong, CxxWrap.CxxLong),
                    (Rational, Union{Base.Rational, Rational}),
                    (TropicalNumber{Max, Rational}, TropicalNumber{Max, Rational}),
                    (TropicalNumber{Min, Rational}, TropicalNumber{Min, Rational}),
@@ -136,6 +140,7 @@ for (pmT, jlT) in [(Integer, Base.Integer),
     @eval begin
         convert_to_pm_type(::Type{<:AbstractMatrix{T}}) where T<:$jlT = Matrix{convert_to_pm_type($pmT)}
         convert_to_pm_type(::Type{<:AbstractVector{T}}) where T<:$jlT = Vector{convert_to_pm_type($pmT)}
+        convert_to_pm_type(::Type{<:AbstractSet{T}}) where T<:$jlT = Set{convert_to_pm_type($pmT)}
     end
 end
 
diff --git a/test/arrays.jl b/test/arrays.jl
index a16e691d..6dbbe184 100644
--- a/test/arrays.jl
+++ b/test/arrays.jl
@@ -148,6 +148,6 @@
        @test pma isa Polymake.Array
        @test eltype(pma) <: Polymake.StdPair
        @test first(first(pma)) isa Polymake.Set{Polymake.PmInt64}
-       @test last(first(pma)) isa Polymake.PmInt64
+       @test last(first(pma)) isa Union{Int64,Polymake.PmInt64}
     end
 end
diff --git a/test/convert.jl b/test/convert.jl
index f98f6ce1..53254b39 100644
--- a/test/convert.jl
+++ b/test/convert.jl
@@ -11,7 +11,7 @@
     @test Polymake.convert_to_pm_type(Base.Vector{String}) == Polymake.Array{String}
 
     @test Polymake.convert_to_pm_type(Base.Vector{Base.Set{Int64}}) == Polymake.Array{Polymake.Set{Int64}}
-    @test Polymake.convert_to_pm_type(Base.Vector{Base.Set{Polymake.Integer}}) == Polymake.Array{Polymake.Set{Int64}}
+    @test Polymake.convert_to_pm_type(Base.Vector{Base.Set{Polymake.Integer}}) == Polymake.Array{Polymake.Set{Polymake.Integer}}
     @test Polymake.convert_to_pm_type(Base.Vector{Base.Set{Int64}}) == Polymake.Array{Polymake.Set{Int64}}
 
     @test Polymake.convert_to_pm_type(Base.Vector{Base.Vector{Int64}}) == Polymake.Array{Polymake.Array{Int64}}