Hi andreas,
i managed to solve this problem using table readers like opcode "table".
This kind of opcode are interesting because the way they manage the gen
routins in the time domain is not connected to the frequency of an
oscillator. Moreover any length is  available just putting zeros to the end
of the function and reading the table up to the desired point.
example:
; Orchestra
 sr     = 44100
 kr     = 4410
 ksmps  = 10
 nchnls = 1
instr 1
kindex line 0, p3, 256  ; line going from index X0 to Xn. Doesn' t matter if
Xn is not the end of the function
kamp table kindex, 2  ;
asound oscil kamp*18000, 440, 1
out asound
endin

; Score


f 1 0 1024 10 1     ; sinus
f 2 0 512 7 0 6 1 50 .8 100 .8 100 0 256 0 ; my breakpoint file + zeros to
the end of the function (ordinarily a power of 2 or a power-of-2 plus 1)

i 1 0 1
e
Best

dott. Francesco Barreca
MNT, Conservatorio G. Tartini
Trieste, Italy